We recently attended a Marriott sales presentation in Orlando, and I can honestly tell you that we were lied to at least 3 times, possibly four, by our salesperson.
The guy can deny all over the place and say that he didn't lie, but he did, and I am relatively certain that you were told some untruths during this presentation, because it seems to me that Marriott salespeople are getting hungrier than they used to be.
I am hinting here that you probably didn't get the straight skinny on the timeshare you purchased, so hanging around here for answers might be just the thing to help you with a resale somewhere.
Others have given you some great advice. You should rescind immediately, and send your rescission via registered mail, return signature required.
Fortunately for us, Rick and I are very knowledgable about timeshare and how things work, so when this person lied to us, we recognized two of the lies. Only one item was I unsure about, until I asked here.