We have been scammed on a timeshare sale

A company offered us money for our timeshare. We signed a document that was supposed to be an agreement for the price, not the sale yet. They were supposed to send it to our timeshare co., but instead had someone impersonate the company and ask for closing costs that should be sent to a mexican bank. We called our timeshare co. and they said it is likely a scam. We never sent money, and now they want to charge us for legal costs or take us to small claims court. We don't know what we should do next.