In January, I had a Hot Toys Padme Amidala from Attack of the Clones that I put up on eBay. After bidding, it went for just north of $400. I shipped it to the guy, and when he received it he immediately left me positive feedback thanking him for such a great item and how pleased he was considering the cost.
A week goes by and I receive a new message on ebay from the buyer. He's sent pictures of the shipper box and outer box, both with a big hole in them. He says the figure is undamaged, but it's worthless now because the box is damaged. He wants to get a refund and "offers to return it" (what am I supposed to do with it now?) Thankfully, after many back and forth conversations with ebay customer service, ebay had my back and he didn't get shit. What did it was the initial positive feedback he had left. The boxes were pristine when I mailed them, and if there was any damage it would have happened from the carrier (UPS), which I found out you're still responsible for as the seller. But honestly, I'm pretty sure the holes were put in afterward...maybe a significant other wasn't happy about the $400 purchase and demanded it go back lol
In March, nearly two months later, I received another notice stating that his bank was investigating because he had challenged the purchase on his card. I contacted ebay again, and they told me to straight up ignore it and they'd take care of it. In April I received a final message telling me his bank sided with me and it was finally all over and done with.
Anyway, that's the only bad thing I've experienced while selling. It all just seemed very scammy, especially after receiving the positive feedback right away and then he waited a week to complain. I've heard people say you shouldn't sell high-value items to buyers with small feedback numbers, or bad feedback in general, but I don't know how to prevent that sort of thing as the seller. I could cancel the order after it's purchased, but it seems like that would just garner negative feedback for me and I like my pristine 100% positive number lol