You seem bent on arguing with me. First you say that Wyndham had received your rescission on the 20th, then you say you mailed it on the 20th, and I just pointed out that Texas law would require that (if your contract was signed on the 13th) it be mailed on or before the 18th. Frankly, if it was MY $58,000, I would have been pouring over every word of that contract.
Truly, I hope that your defense of 'not having the contract' works. If they didn't send it with you out of that sales room on the 13th, that was just sloppy execution of the contract and they deserve to lose the sale and their commission.
I wish you well. I hope they honor your rescission. I've told you what the applicable state law is, and I'm done here. Please let us know how it works out. If it turns out you are a new timeshare owner, you can find lots of information on how to make the most of your ownership. And if this is the case, DO NOT fall for any of those upfront fee, 'Get you out of your timeshare' outfits. They are ALL just scams to take more of your money. There are no magic words to make a lawfully drawn contract end.
Good Luck!
Jim