We had the same experience at the Riviera Maya location 1/28/11. Many things were promised by the salesperson about the Grand Paradise Club membership which turned out to be not true. He assured us repeatedly that we had 5 business days to cancel per Mexican law with full refund. When we tried to do that, we were told that no refund was possible so we are following up with our credit card and Profeco (Mexican consumer protection agency).
Stay away from these salespeople as they are not ethical!
They will say anything to make a sale but are dishonest.