Most eBay sellers are not verified manufacturer's representatives and cannot fix problems with the stuff they sell.
This doesn't mean their products are not the real thing, just that the deals you find are usually not covered by manufacturer's warranties.
While the manufacturer would want the product back for repair, replacement or refund, this can only be done by the first buyer (your seller) or an authorized dealer (not your seller).
Ask the seller for a refund on return of the product. If he says yes, return it WITH DELIVERY CONFIRMATION, and when he refunds the manufacturer and the warranty is his problem.
If he refuses, or if he does not refund promptly on delivery, open a case with Paypal "not as described". You only have 45 days from purchase for this, so don't mess about.
PP requires confirmation of delivery. In North America, this would be Expedited Parcel. Without DC, you will lose the dispute.
You will pay for the return shipping. It is possible, but unlikely, that the seller will refund the return shipping. Ask politely anyway.
You have 60 days to leave feedback. Take your time about that. (let him sweat a bit)
