I sold an omnichord for a good amount, the piece was in mint condition still had original plastic from the 80’s. Everything worked fine. When the item arrived to the buyer , they said a button was missing and it didn’t work. I issued a refund but still have received my item back. They won’t return my messages. This was my first sale on eBay so I’m not sure how to go about this situation and how to get my item back or get the money for it.