Sooo, if I read you correctly, you sent the buyer the wrong item and they filed a dispute with their Credit Card.
If they did not open a return case with eBay, no way are you getting the item back.
The credit card chargeback from the buyer is the trump card. Case closed. EBay has no say in a Item Not As Described credit card dispute.
You hosed yourself in this case. What is it you would expect eBay to do for you? You sent the wrong item and buyer did not like it and went thru their bank leaving eBay out of the picture.
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