You are out of time to start a return through Ebay and this is entirely between you and the seller.
If you bought from a UK business seller, they may have an address, a phone number or an alternative email you can use to contact them.
However, online warranties can be very difficult to enforce.
As you have bought an item online which is not fit for purpose, you may still be in time to start a chargeback with your payment provider - generally they allow 120 days. (Not Paypal.)
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)