Scummiest eBay behaviour I've ever had is I won a brand new £500 Homebase fireplace in a competition, which was amazing as we couldn't afford to buy one.
It was delivered, we opened the box and immediately realised it wasn't right for our living room. I took some pics and resealed the box and stuck it on eBay with a reserve that meant if it sold we'd have enough for another fireplace, or at least most of the money towards it.
In my listing, I showed a link to Homebase, showing its current price, so buyers knew they'd get a bargain.
Ended up selling it to someone, who bid the price it was going for in Homebase. I thought this was odd, but didn't question it. Maybe they didn't live near a Homebase?!
Sent it off in the box I'd received it in. Sent with Parcel Force, fully insured.
Two days later. Buyer raised a dispute. Says fireplace was damaged. Sent pics of damaged box and fireplace. I asked why they signed for it and apparently they thought the box was just damaged. 
PayPal refunded them and they sent back the fireplace. The box damage didn't correlate with the damage to the fireplace and it didn't look as pristine. I think the buyer either already the same fireplace and it broke and they swapped it for mine and sent their broken one back. Or they damaged mine trying to install it and damaged the box to support their claim.
I tried claiming through Parcel Force. They refused to pay out, claiming it wasn't effectively packaged. Even though it was in the manufacturer's packaging it was delivered to me in.
Great big fucking scam. I was then £500 down, no new fireplace and a heavy broken one to discard off. I was gutted. Really upset.
Some people are wankers.