We get many questions about items which develop faults after eBay's 30 day money back guarantee has expired.
Many eBay sellers don't want to know about after-sales problems. I presume you've checked whether it's covered by any manufacturer’s warranty? Unfortunately, maker' warranties are often invalid for items bought on eBay.
It's possible that your credit or debit card issuer may be able to help, if that's how you paid or funded the payment. Or, if the seller is a registered UK business seller, you may have some statutory consumer rights. However, enforcing them against distant, uncooperative eBay sellers may be difficult or impracticable. There is plenty of information online, or contact Citizens Advice. If they're a UK registered business seller you can also consult trading standards.
I'm afraid that these are the risks of buying from unknown sellers on eBay. The user agreement does warn buyers that "eBay does not guarantee the existence, quality, safety or legality of items advertised, or the truth or accuracy of descriptions". Buying on eBay is not like buying from the shops.
