With no tracking, that is, tracking to show delivery was made on time, then a case will be escalated for a refund if you do not refund in time, so eBay gave you the correct information here.
It does happen that after a refund the item turns up , but as the eBay transaction closed with the refund, eBay cannot help you further here, and it's now between you and the buyer to recover the cost of the item.
Send the buyer a polite message that as tracking now shows the item delivered please can they now repay you which can be done by cheque, bank transfer or a PayPal Friends and Family payment. Or you can send them a PayPal invoice for the amount.
If PayPal is used, email addresses need to be exchanged, this can sometimes be found with the order details >> Show Contact Info. If not and you need to ask the seller for this, make it very, very clear in your eBay messages, as eBay do read these, the reason for these exchanges. Make it clear it's not to be used for an off eBay sale.
Nothing unfortunately to enforce them to do so.
@rinnkhr
