I would call the resort ( if it takes many times so be it) and see if your MF will be honored ( probably only if you sign the letter). If you don't feel comfortable with the response you get or you don't sign the letter I would look elsewhere to stay. Or you can write off the MF you paid and check on booking there as a hotel. I know your upset the way things are but you have to pick up the pieces and deal with what your options are. You have some time at least to look at other options ( there will probably be alot of people looking for other options soon, so first come first served).
SXM??? Wendell