Hello, Did you buyer open a "Significantly not as described case"?
The core issue may not be the delivery and receipt of the item - your buyer seems to be saying the item differed from the eBay listing description. This may be true and it may be false - but in either case as the seller you should have approved a refund, issued return postage and gotten your item back in your hands for future resale.
It's best to come here when a case is opened to get some assistance as sometimes eBay customer service representatives with good intentions will offer sympathetic words but miss the big picture. And the big picture is that eBay rules favor buyers and the goal is not to be right or sometimes even win as case - and that is difficult but to get your item back in your hands - not to gift the buyer with the item AND a refund. That scenario will play out if you as the seller don't act quickly to figure what type of case was opened. In this case, a SNAD case means the seller is on the hook for the full return (there are exceptions if you offer free shipping & free returns).
In your case, did the buyer get the refund and the item you sent? I am hoping not.................I understand how frustrating this can be.........
