I just moved to an apartment, and starting to put up some decorations. This is a wall that I share with my next door neighbor, which stretches from the end of the living room (next to the balcony door) to the end of my open kitchen.

I recently nailed in a picture hanging hook towards the balcony end, which goes in about 3/4" and didn't have any problems.

Today, I tried to hang some wall planters on the same wall towards the kitchen end, which came with EZ anchors.

I tried to screw in with just a Philips driver, per the instructions, but it was really difficult, so I got the drill out and drilled deeper than the anchor's length (the entire drill bit length). I would say the first 3/4" drilled like a regular drywall, but the next 1.5" was a bit tougher. Then I screwed in the anchor, and after making a gigantic hole, the anchor only went it a little deeper than the skinny half, then broke off.

So instead of using this anchor, I decided to use an anchor I've used before, and proceeded to drill another hole next to the failed hole. Except, the drill bit only went in halfway, and no matter how hard I pushed, it would not go in! (then my drill bit slipped sideways and connected with the failed hole to create a giant gash)

I am a little perplexed now, and don't want to ask the building management, because I don't want them to know that I drilled a giant 1" gash on the wall. Any idea what could be happening? It didn't seem like there was any metal back there, and I know there isn't a stud there (and my drill can easily drill through a stud).

I thought about trying another hole elsewhere (I'm trying to hang 4 of these planters), but have PTSD from this experience now...