Regrettably, warranties on eBay often prove worthless. Sellers may claim a warranty, but when things go wrong many don't want to know. Even manufacturers' warranties are liable to be invalid for items bought here.
eBay will not get involved after their own 30 day money back guarantee has expired. Depending upon how long ago you bought it your payment provider e.g. credit or debit card issuer might be able to help, if that's how you paid. Otherwise, if the seller is a registered UK business seller your statutory consumer rights should apply - although enforcing them against distant, uncooperative eBay sellers may be difficult or impracticable.
Good luck, but buying from unknown sellers on eBay is not like buying from a shop. The user agreement even warns buyers that "eBay does not guarantee the existence, quality, safety or legality of items advertised, or the truth or accuracy of descriptions". Would you have bought this from a shop that said this? eBay is a jungle.
