We don't really have handyman skills BUT I am a super quick learner. I am willing to try and then call it quits if we need to bring in the big guns. Yes - you are correct - contractor is not only incompetent and lazy but turns out he's a real a-hole too. I will post pics shortly.

Here are some photos. Happy to provide more if needed.

Did it overflow from out over the tank on the back or from the bowl?

From the bowl.

OK sounds like you have two problems. Most toilets when filled about 3/4 full empty themselves. You might have a clog. Get a bucket and fill with water and fill the bowl with water till before it overflows. If it doesn't go down you have a clog. Get a good plunger made for toilets and see if you can dislodge the clog. If you don't know how to use it just look on youtube. If the water wouldn't go down you will need to get a plumber to snake it out. Do not use anything like Drano. Your second problem is your ball in the tank is not seating correctly. Some times is just an adjustment or he put in the wrong ball. First get the overflowing from the bowl fixed then concentrate on the ball. Have the plumber look at both if you can't get the clog fixed yourself.

1) You say the flap doesn't go down after flushing. Is that because the curved arm connected to the flap chain is getting hung up on that rectangular black overflow pipe?

2) The black and white tubes that are connected to the flush valve look totally wacky. Is that the "fix" done by the contractor?

I have no idea why the flap isn't going down and didn't see an obvious obstruction but will examine it further. I do know how to snake a toilet - woohoo! We had to learn that for our kids bathroom when they do things that kids do. I will check to see if it is a clog, but I really don't think so. Prior to completely breaking down, we noticed that the water was running an awful long time post flush. Can that signify a specific issue? He supposedly didn't touch anything except swap out the flush handle so not sure how he could've messed up the ball.

Reemanu-

Observe what happens with the lid off when you use the flush lever. Does it move smoothly? Does it come to rest on that black, upright tube? (It shouldn't.) Is there a little slack in the chain? (There should be.) Then report back here.

Also, overflowing from the bowl is typically associated with a clog. You may have more than one issue here.

Alright Reemanu, ya kids like to clog toilets. When you said he installed a flusher I thought you meant the whole thing. I'm with kudzu9 the arm might be getting caught up on the overflow (black rectangular thing). It could be many things. The chain is to short or another thing. You pretty much have to see it in action to see what the problem is.

Reporting back! The flusher is moving up and down no problem. It isn’t touching the black tube at all during the process either. The chain has a little slack but maybe not enough? Also the water doesn’t stop running unless I manually left up the black stick thing attached to red cap. I get scared the water will overflow so I end up turning water off at the wall. The water in the bowl does eventually go down on its own once water is off. I am attaching some more close up photos in case anything strikes you as odd.

Based on my research and assessment I believe we need to replace either the fill valve, flapper or both. I called some local plumbers who are quoting upwards of $150 to come out and change just the flapper. Looks like replacement parts are pretty cheap. Are these two fixes simple enough for us to try on our own before shelling out more $$$ or is it best to leave it to the experts from the beginning?

A new fill valve and flapper kit are about $15 total, and it's the easiest DIY plumbing job I can think of. If you've done one before, 10 minutes; since you haven't, maybe 20 minutes. There are plenty of YouTube videos on this so I won't describe the steps, but post here if you have any problem.

There should be an adjustment on the black stick

Judging from the pictures, the flapper's arms don't extend far enough to let it seat properly. One piece toilets (without a separate tank and bowl) often require special, more expensive, hard to find parts. Do a web search for your particular model and you'll probably find the correct part. Once you have the right flapper, installing it shouldn't be difficult.

A couple of things to consider, basic info on fill valves and overflow tubes:

Your second-to-last photo.

The red cap has a black arm coming out of it that leads to an "adjustment knob", you can rotate that knob to adjust the water fill level in the tank up or down. The knob has a phillips head screwdriver pattern molded in to it. You can turn the knob with your fingers or with a screw driver.

Typically you'll turn the knob clockwise to raise the water level in the tank and counterclockwise to lower the water level in the tank. Some are different. Look closely, yours has the rotation directions molded in to it. The other end of the black rod that the knob is attached to is threaded, like a screw. As you rotate the knob, the threading will raise or lower the float that moves up and down on the column under the red cap.

Typically, if the toilet tank fill valve continues to admit water into the tank, the water level in the tank will eventually reach the height of the overflow tube. Your overflow tube is the black funnel-shaped opening above the red flapper. Water in the fill tank will flow into the overflow tube and run into the main bowl. Because the water in the tank never gets high enough to satisfy the fill valve, the fill valve stays open.

With water continually flowing out of the tank and into the bowl via the overflow, the water level in the main bowl will then rise until it is higher than the height of the trap, and then it should self-drain out of the toilet, through the toilet trap, and into your waste pipe.

Unless the trap is clogged, the water in the bowl should not ever overflow the rim. If you've snaked the toilet trap and there is no blockage, there is a chance there is a partial blockage further down in the waste pipe.

Some toilet tanks have a water height fill line molded into the china of the tank itself, or there may be a reference line on the overflow housing. If yours has one, you can use that for a starting reference for the desired water height in the tank. If not, then rotate that adjustment knob so the float turns off the water fill valve with the water level about a half-inch below the height of the opening at the top of the overflow.

A couple of other items to consider:

If the red flapper is not seating properly on the sloped base beneath it, then water can leak out of the flapper and into the bowl. In that case, because water is leaking out at the flapper, the water level in the tank may never rise high enough to shut off the fill valve. Your fill valve will remain open.

A slow leak at the flapper is usually indicated by the toilet fill valve cycling on and off by itself. After a flush it fills the tank and the valve shuts off. A slow leak at the flapper lowers the water level in the tank to the point where the valve opens, and water flows to fill the tank. Repeat.

You have a small black tube that is connected to a larger diameter white tube. After you flush, the fill valve sends some water through that black tube, which then goes into the white tube, and then goes into your toilet bowl. It's designed to add water to the main bowl after a flush, to create an appropriate water spot. If the opening of that white tube is submerged when as the tank fills with water, that can be another way water is flowing from the tank to the bowl. The white tube is essentially acting as an overflow tube.

Wow! Thanks so much for the thorough response MongoCT. I also noticed the water coming from black tube with white end into the white tube isn’t actually going into the white tube. The spray of water is going outside the white tube on top. Is that what it is supposed to do or should the black tube end be fully enclosed into the white overflow tube? Thanks!!

I want to circle back with everyone because you were so helpful! I tried all the suggestions and even snaked the toilet a few times. When one of my 4.5 yr old twins almost had another accident on our newly refinished floors because they had to race upstairs to use a toilet - we finally decided to call in the big guns. We had a hard time finding anyone that could come out before next week except RotoRooter. They didn’t charge a fee to come out but they did quote us $285 to unclog toilet plus $285 to replace fill valve and flapper PLUS cost of parts. I promptly said thanks but no thanks. I then searched yelp and found a local plumber that was able to come out right away for $89 plus $45/15 min. Turns out it was a clog! He snaked the toilet and everything was good to go! He was a good guy and ended up not charging us a penny even when we tried to give him something for his time. So I definitely need to up the game on my snaking skills and you guys were right! We suspect the contractors disposed of things in toilet they probably shouldn’t have since we hadn’t really used that toilet in over a month. In any case, the nice plumber also said our toilet is pretty old school and should be replaced sooner rather than later. He recommended the Toto Drake. Would love your opinions on toilets to consider. Thanks again!

Thanks for the update. Glad it's fixed!

My neighbor had the same problem with a newly installed toilet a couple of years ago. He was doing a remodel with a contractor who got very difficult to deal with toward the end of the project and basically abandoned the job before it was complete. They had to bring in another bioreactor to finish. After everything was complete, they kept having toilet problems, and called the second contractor back in, who finally decided to pull the toilet. What they found in the sewer drain was a bunch of small chunks of concrete that were due to either the first contractor's negligence or spitefulness.

By the way, what did your plumber think of the innards in the tank? Was that actually all ok?

I spoke too soon... It clogged up again in a matter of days! I was snaking it the last time it clogged and eventually was able to get it to work again. One thing I noticed though was there was a yellow wax caught in the snake. It took a lot of effort to clean it out. Could this be the toilet ring wax?? If so, what does that mean? Does it mean the toilet wasn't reinstalled properly? Could the contractors have put wax in our drain? What do we do to address this in a more permanent way?

Currently the toilet works fine if only handling liquid waste. The real problems start if anyone dare have solid waste. Obviously this isn't going to work long term. I want to have my facts straight before I go off on the original contractor and demand them to fix their mistake. He has finally contacted us back and wants to "wrap" things up.

The plumber did say the flap and valve were totally fine and didn't think they need to be replaced. He only said it would clog again and a new toilet is better option than replacing those parts since they seem to be working as they should.

Sounds like you need someone with a camera to look down there and find out where and what the blockage is.

Just a guess, but part of the old wax ring could have gotten dropped down the drain during the toilet install and is causing a partial blockage.

Is there an easy fix for this? Would it cause such massive clogs?

The easy fix is to have it properly and thoroughly snaked. I once had a problem with clogs and overflows like yours, and the culprit was a popsicle stick that some guest had flushed down the toilet. So, yes, a modest, partial obstruction can cause big problems.

Why don't you just unscrew the nuts from the bolts and pull the toilet off of the floor and check the condition of the wax ring? A new wax ring with plastic funnel attached is only like $ 6.50 at Home Depot.