Like so many buyers, you didn't read the warning in the user agreement, that "eBay does not guarantee the existence, quality, safety or legality of items advertised, or the truth or accuracy of descriptions".
eBay also makes it clear that their own money back guarantee only lasts for 30 days. Sadly, many users mistakenly seem to think that eBay will always be there to help them. They won't. After 30 days eBay will have no interest, whatever happens.
If it came with a warranty you need to take this up with whoever issued it. Otherwise, if you bought it from a UK registered business seller you may have some statutory consumer rights. There's plenty of information online, or you can ask Citizens Advice. Unfortunately, having rights doesn't count for much unless you can enforce them, which can often be difficult or impossible against distant, uncooperative eBay sellers.
The fact is that buying items unseen from unknown sellers here is risky, as even eBay acknowledges in the user agreement.
We don't know how you paid, but if by credit or debit card you can try asking your card issuer whether they can help. Especially a credit card, which adds statutory card purchase protection.
