You are a Private seller so should be using Simple Delivery.
Under SD rules, as the buyer has not received their item they should open a case for item not received and eBay fully refund the buyer everything they paid, and you keep the full payment.
Did this not happen ?
You now have the item and should have the original payout so in effect if you do relist it again buyer pays again and there are 2 payouts received for the one item.
This must happen a lot and eBay have not made it clear if they do then retrieve one payout if 2 are received, but I somehow doubt this happens ? 🤔
@maad2014