If it's polished, it should be uniformly glossy. Water should pool on top of the countertop to be wiped away. It should not penetrate.

Talk to the fabricator. It's their job to prove it's done right.

Sealer is not generally applied in the field any longer. It is either done at the wholesale level of the distributor, or in the shop of the fabricator. Sealer doesn’t make a stone waterproof, but it does slow down liquid absorption in order to allow you more time to clean up the spill. The gloss level of a stone has zero to do with being sealed. That has to do with being polished, which is also done at the quarry.

You need to leave it alone for now.

Sprinkle a little water on the top. Does it bead up nicely or does it soak in?

As Joseph said, put a few spoonfuls of water on the countertop and leave it for hours. I leave mine overnight. When you wipe up the water in the morning, if you can see that any of the water has absorbed into the stone, your countertops need more sealer. (And be aware that different parts of the stone have different densities so you should put spots in different areas.) Applying sealer is not hard -- your contractor should be able to handle it if he has sealed stone before. The important thing when sealing granite is that you never allow the sealer to dry on the countertop. (For this reason, I find it easiest to work in small segments.) Also crucial is that the countertops are clean and dry before any sealer is put on. Home Depot should sell a good granite cleaner (that you can use on your quartzite) that you can use before they are sealed. If you are seeing swirly marks, try wiping the countertops down with a granite gold-type product and then drying them. If they aren't just sponge marks, it could mean that a sealer was applied, but wasn't properly removed.

Can you post any pictures?

If you do need to seal--and I actually don't think you do--this is a 5-minute job that does not require your contractor to come back to do. It does not need any special skill - if you are able to wipe lightly in a circular motion, you can do it. In fact, if your counter is the type to need annual resealing, you will have to do this yourself eventually anyway. Buy the smallest bottle of sealer you can find at HD. It will still outlast you in this kitchen, as you just need a very small amount in order to seal. (Don't get one that says "enhancer", you just want "impregnator"). Follow the directions on the container. Seriously, 5 minutes or really 3. It'll take longer to clear your counters of your toaster etc than it will to seal.

Having said all that, I am not sure you need to seal. There is such a thing as too much sealant, and/or sealant applied when it is not needed. When that occurs, your counters will show what is called "hazing" as the sealer sits on top and doesn't absorb, either because there is already sealant applied, or because the stone is so dense it doesn't need sealer (I haven't sealed my granite counter in years because it is a dense-type stone). One way to tell if you have hazing if you aren't sure is to drag lightly a dish or bowl on the counter, and if it leaves track marks, your sealer is not needed and hasn't absorbed. That could be what the "swirly marks" you mentioned are, but we can't tell without photos. The drag marks are in the sealer layer, not in the stone. You can remove it with acetone; there are threads about this.

http://www.homedepot.com/p/Miracle-Sealants-16-oz-511-Impregnator-511-PT-SG-H/100672948

I am not sure I agree with leaving water overnight as a test. It will be sure to evaporate regardless. Leave the water 15 minutes. If it beads up and doesn't absorb, you don't need sealant.

ETA: This article says 30 minutes tops and you'll know. https://thegraniteguy.us/granite-countertop-blog/water-test-seal-granite-countertops/

maybe from my rough sponge?)

How rough? And why a rough sponge on your expensive new counters? Just a regular sponge, please, or a Dobie sponge (used to clean Teflon pans).

Is it polished or honed?

I agree with the others who say you likely don't need more sealer.