Can't tell you very much without more details, but this is rather typical of thieves and eBay con artists. Was the item returned? If the buyer can't produce a tracking number with del confirmation, paypal should rule against them, but you'll have to contact PP and stay on top of it.
Unfortunately, paypal nearly always sides with the buyer in a dispute, even when it is clear the buyer is lying. I had one instance where the buyer first asked for a refund because "We changed our mind" and then later claimed the item was "damaged and not as described". Lucky for me, the buyer could not produce a tracking number. Paypal eventually denied the claim, but NOT based on the obvious fact that the buyer was making a totally false claim.
Paypal favors the freeloader over the paying customer in almost every case. Great isn't it ?
