I occasionally sell items on eBay and use PayPal to collect payments. I depend on PayPal who has the relationship with the purchaser to tell me when they have received funds and it is safe for me to send out the item they purchased on eBay. I happened to have sold a 1-year subscription to XXXX XXXX that was paid for through PayPal. PayPal/eBay sent me the notification that I was okay to provide the buyer with what they had purchased. It happened to be an electronic key that I provided to the buyer through Ebays messaging service. PayPal came back to me saying they payment was returned by the purchasers bank and that it is not covered by their Payment Protection. So ultimately PayPal received payment, told me it was safe to deliver the product, payment was returned by the bank, and I am liable for the full amount. So I am out the {$57.00} that I should have earned by selling the product as well as fees I had to pay to eBay which is roughly 10 % of the purchase price. The customer used the product, and I paid for it. It was likely a fraudlant transaction from the beginning but Ebay and PayPal allowed it to happen. 
