This is 99% likely to be a scam, because you can acquire timeshares in Mexico for free, so no knowledgeable company will pay for them.
This is how it usually goes: You sign their phony paperwork and things seem to be sailing along towards a big check, when all of the sudden the company tells you that you have to pay some kind of large fee to proceed. They may call it taxes, escrow, closing costs, title fees, commission, or other words that "sound" legit.
They assure you that the funds will go into a licensed escrow account and you will be refunded after the close of escrow. They will even name a well-know escrow company and send you a link to the company website.
After you agree to pay the fee - they will send you a link to a bank account to wire the money to.
After you wire the money, they will disappear with your money and you will not be able to contact them - because that's all they were after. Even worse, they had you (unwittingly) wire the funds outside the US - and the money is long gone.
There is no buyer.
There is no offer.
There no deal.
It's just a scam...