The same thing happened to me a bout a year and a half ago. What's wierd is the letter/email you got was almost identical to mine. I did get a cashier's check and went to the bank. Feeling something wasn't right (they sent it for too much and wanted me to send them the balance back to them in a M.O.) I asked the bank to check it out. They got in touch with the local authorities, the FBI I think, and found out this was probably a scam. I basically lost $14.00, in paperwork fees, but I went with my gut instinct and foiled their plan to get my vehicle and cash. I would send any info you have so far on these people to your bank and/or local authorities. I hope it all works out for you.