Ive had a few false promises like this before, if they havnt done the refund, it normally means they’ve lied to move you on. Unless they’ve said allow 24-48hours for the case to update then I would keep calling and giving a brief description and say the last call handler said they were closing it in my favour but nothing has happened, please can you help me with this.
It was 50/50 imo after lots of returns like this that they sided with you. You have the fact the item has been graded by a known 3rd party, but they could have just said sorry its best you take the item back.
I think you have a pretty strong case. Thankfully PSA are a globally recognized authentication service and you can provide all the details for them to check. I would just keep trying eBay. Eventually you will get through to someone who will actually update your case. I have had this before and it took several calls before I got through to someone who actually helped me and didn’t just try to get me to leave as quickly as possible.
Final update: After 5 weeks eBay have closed the case and the funds were finally released from hold. It’s absurd that a buyer can make a ridiculous claim, with no evidence or reasoning, and keep such a large amount of money on hold for so long. I think this would have dragged on for a lot longer if I hadn’t made so many phonecalls to eBay support. If you find yourself in a similar situation don’t trust the automated system to resolve anything.