Rule #1 for eBay sellers: if a buyer says, "I no longer want it", or "it doesn't match the description", your reply is ALWAYS, "OK, return for full refund".
Rule #2 for eBay sellers: never, ever send requests for payment. Either cancel, or open the UID.
Rule #3: if a problem buyer says anything in a message that casts doubt on the veracity of his claim, as your buyer did, CALL eBay (during the day, to make it more likely to get a rep in the USA) and ask them to review the messages and remove the neg and any defect caused by the claim.
That's one reason why I stated when payment is due and take lots of photos of the gear.

