EBay's money back guarantee only lasts for 30 days. Paypal's buyer protection policy lasts longer, 180 days, but only covers the condition of items on delivery, not faults that occur in use. Neither will get involved in warranties.
Any responsibility now rests with the seller. If they're a UK business seller, in theory you should have the same statutory consumer rights as if you bought it from a shop. If they're in China, there's nothing you can do.
