Hello, I live in Massachusetts. Two years ago I bought a used All terrain vehicle from a dealer. It came with the release of lien from the bank and the title. I sold it two days ago and now the guy wants his money back because he cant find the VIN number on the bike. Before purchase, him, myself and his friend looked for 45 minutes and could not find it. He purchased it anyway saying "the numbers must be under the plastics somewhere." (his friend agreed) Do i legally have to refund his money?