From the facts you've provided above, if you want out of this contract you should seriously consider hiring an excellent attorney immediately because it sounds like the seller has already given the appearance of dishonesty and has not dealt with you in complete good faith.
First, if there were material terms of the contract that weren't disclosed by the seller prior to your signing the contract, you can probably cancel the contract. There may be some issues surrounding your failure to read everything before you signed the contract. You are viewed as having accepted all of the terms included in any contract you sign, even if you didn't read them.
You should act quickly to preserve all the rights to cancel that you are due, and to have the best chance of cancelling the contract.
By the way, if you send the seller some mail, send it by overnight delivery with required acknowledgement of receipt.
Good luck. Mark Arend.
There are many similar questions and answers about timeshare cancellations on Avvo, you should review them. And yes, hire a qualified real estate lawyer in your area immediately.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.