Very likely a scam if they contacted you to offer to sell your timeshare. Sorry, that should be definitely, not very likely. Looking at their website, the only properties they list for sale are Vidanta timeshares at the Celebrate Park Resort Hotel, which is not yet built, but they tout elsewhere that they are brokers for other properties. If you're looking to get rid of the Mayan Palace RTU, you might consider selling it yourself on eBay, in the TUG marketplace, or giving it away in the free timeshares forum here on TUG. Don't expect to get anything near what you paid for it, of course.
I also own at Vidanta and frequently am contacted by companies that offer me the world for my ownership because it was a fabulous and wise investment I made. I sometimes talk to them for a while if I'm bored, but realize that they are always scammers.