My eBay selling goes back to '97. Actually more buying since inception, but probably five hundred sales during that time. Only a few less-than-smooth transactions, but still managing to keep my record spotless. Some ten years back, one buyer did not like a couple of tiny scratches on an unused wheelset. In my listing, I mentioned shopwear and tried to disclose in my pics. Dude went berserk on me. He got a full refund and sincere apologies, but nevertheless left my first negative. eBay gives the seller the opportunity to write a blurb, so I expressed my surprise about getting my neg despite issuing a full refund. Slipped in a little "avoid this eBayer" bit, too. Somehow it worked, because he retracted the neg.
Anyway, I always try to give good service, yet sometimes you depend on luck for every transaction to go well. Still, way better than FB Marketplace or craigslist, where you're forced to meet people in person. And they suffer no repercussions for botching a deal.