I shipped it back with a label provided by ebay, so they should have that. Really glad I did. At first, the seller wanted me to ship it back on my own and claimed he would add the return shipping to the refund. I told him I'd only use ebay's shipping. I figured it was just that he was a new seller and didn't know better. Now I'm realizing how much of this process was shady in hindsight.

So what is ebay's policy or procedure when it comes to claims like this? The seller says the serial number doesn't match the one he sent me. I didn't look at the serial number (or even know that one exists), but if he's selling a bunch these refurbished, he could easily produce one with a different serial number and claim that as 'proof'.