eBay is one of the safest platforms to buy anywhere. I have been selling on eBay since 1998. And you should know that as a buyer if you don't like what you bought on eBay, within 30 days, you will get your money back regardless if the seller says no refunds. eBay will side will the buyer 100% of the time "unless" they think there is fraud involved. (on the sellers part)
Let me add a little personal experience. I wanted to build my own LP ultrasonic cleaner. So I bought a generic ultrasonic cleaner base and parts that would work to raise and lower the LP's. I had things to do so it sat around for a few weeks before I put it all together. Well, the heater on the unit did not work properly and I asked the company for an exchange. They said no, so I contacted eBay. They were polite, but told me after 30 days they couldn't help me. I admitted I took to long, reference my longevity on eBay etc. Still no. However then she said: "did you pay by PayPal?", why yes I did, "Oh good, because you get a 60 guarantee with PayPal. Never heard of such a thing. Long story short I filled a claim with PayPal and received a full refund within 48 hours.
Now what is worse about the process, for a seller, is that PayPal did not require me to send back the unit before they issued the refund. I did return it but there was no requirement to do so.