Sorry for the late reply, I've just seen this question has gone unanswered.
eBay do not offer warranties or guarantees on items, just that they are just as described on receipt. If they are not, a buyer has 30 days under eBay's 30 day MBG, Money Back Guarantee policy, to return the item for a full refund.
If the 30 days has lapsed and you bought this from a Private seller you are too late to claim a refund.
If purchased from a registered UK business, who offered a guarantee and is now not upholding this, then turn to Citizens Advice for your next steps, if you wish to take this further.
@denke-4307
