It has happened to me too, with a full established website.
And we're talking about $3,xxx .
The buyer paid me, received the domain, i have installed the website, configured it, got it active and full working, and after few days of no replies to my emails, he has opened a dispute on PayPal.
Why i used PayPal? Because i was unexperienced. It happened 3 years ago.
I have called PayPal almost everyday, and thanking to GoDaddy (yes!) i was able to show them the transfer has been completed and the website was owned by the buyer. Also thanking to the hosting company where he used to have the VPS on, they have confirmed to me and PayPal the owner of the specific VPS was the buyer.
After 15 days i had my account working fine and my money in my account
His account has been blocked by PayPal and deleted from eBay (he insisted to complete the deal on eBay, i accepted because he had more than 500 positive feedbacks).
I also reported him on here, on DNF and on Sitepoint, and his accounts have been blocked there too.
PayPal has a policy of not refund buyers for not tangible items. At least, they TELL that. In really they don't respect their own policy.
I had to demonstrate them everything, otherwise the money would go back to the buyer. Even if they write they consider electronic items as not tangible ones, guys at the phone used to repeat me "please demonstrate us you have been frauded and not have frauded the buyer or we must refund him".
Weird.