Not so long ago, I bought a mains lead on ebay. I found, by a lucky chance, the there was no earth connection, so I arranged to send it back. I took it to my local post office, got a receipt, then a message from ebay noting its postage. Then a message from the vendor saying it had been received, and then a refund reached my PayPal account.
Yesterday, the package arrived back here with a Post Ofice label saying "addressee gone away". Obviously never received by the vendor - yet I got my refund.
Anyone any thoughts?