My new tub is SLLLLLLLLLLLLLLLOW.

Before you read further, keep in mind that my contractor is USELESS and god only knows if he had a licensed plumber do the work on my bathroom (although he claims he did). I've been using the new tub for a couple of weeks now. To my knowledge, the drain was not moved, and the old tub worked perfectly - no water accumulation even with the tub tap on full force.

The new tub drains REALLY slowly - like, if I take a normal 10-12 minute shower, I'm standing in water past my ankles by the time I'm done. I pulled out the stopper partway the other day to see if there was hair or something clogging it, but there really wasn't anything visible (except some paint, so I know they were dumping out paint water in the tub. I'm sure that's good for pipes). In my efforts to clean it, the stopper came all the way out (I assume it was improperly installed) - irritating, but not that big a deal, since I would prefer to just put a drain cover over the hole to catch hair and put in a rubber stopper on the rare occasion that I take a bath.

Anyway, once the stopper was completely removed, the drain started working a little better, but not much. I tried Drano (the foaming pipe snake kind) to no avail. I'm concerned that my idiot contractor installed the tub/drain incorrectly, and that I'm now going to be stuck with a really slow drain forever. Any thoughts? How difficult will it be to fix if there really is something wrong with the drain? Help, and thank you!!!!!!