Clarifying, this company is what is commonly referred to here at TUG as a "postcard company". Their "offer" will be to relieve you of the burdensome ownership of your timeshare, which everyone knows (they will say) will haunt your heirs, cause financial problems for you because of rapidly rising MFs and special assessments, etc. They will likely also falsely claim that you can deduct the loss on disposition, including what you pay them, on your tax return. All of this in exchange for you paying them a lot of money. Yes, you paying them!
What Ed referred to, if it's not clear, is that their $25 check won't bounce. That's the only one they will offer to give you.
Stay away and use the time-tested methods in the "how to sell" article located at the top of the list of topics for this Buying, Selling, Renting forum to dispose of your timeshare.