I've been buying things from Ebay since there was an Ebay and I do it very carefully and I've never been burned yet. I only buy from sellers who allow returns and who have at least a 99% approval rating and have a lot of sales.
I did once buy a Kobo Aura from Ebay and the guy sent me a Kobo Mini. I emailed him and he gave me a refund right away and told me to keep the Mini. I gave it to a neighbor.
Another time I bought a old used handheld computer and it's condition wasn't nearly as advertised. I emailed him and he offered to give me a refund and let me keep the device. I decided that even though it didn't match his description it was still okay and if I'd known it's condition I would have bought it at that price anyway so I told him to keep the money and I suggested he be more scrupulous about his descriptions.
In the first case I'm convinced it was an honest mistake. In the second case I'm less sure it was a mistake but I got what I wanted at a good price so I didn't feel bad about it.
Without exception all the rest of the probably over 100 items I've purchased from Ebay for myself and my neighbors have been just fine. I always have assumed that eventually I'll get burned but I've saved so much in the meantime I can afford to get burned.
Barry