Hi pal just don't reply or if you do just tell them to take it up with the police its there son who is the thief not you , they will have to open a case against you to start the ball rolling to get there money back. they have already sent you an email stating there son bought it and nothing to do with a faulty ,damaged,not as described item etc. Finish transaction let them go to the police its there son who will have to pay back not you and save the messages