Paypal ALWAYS sides with the buyer. On the recipt that you received does it have the address of the buyer on it? If so, scan it, send it to paypal with the claim that he is trying to scam you. From the conversation you had with the dude he sounds sketchy. Just his tone sounds like one of those people on craigslist that try to sell you their 2008 BMW for 4000.
Are you sure about this? I thought you could leave buyers no-paying notices. That was about 3 or 4 years ago, mind you.