judd - it sounds like they havent really given you a chance to rectify the problem. My suggestion would be to take it and get a quote on repairing it, by someone you know or trust, not someone they have suggested. Altho, it seems like it has gone beyond this now.
Also, if a forum member has threatened you I suggest you pass on the details to the police with email correspondence etc. Also may as well post their username as we dont really want people like that here.