If you are still within 30 days of the item's las estimated date for delivery you open a case with eBay and the case will enforce the seller to pay for that fully tracked return postage if they wants the item back first.
If you have gone over this period, you can try and claim with Paypal, but here you pay for that fully tracked return postage.
Neither Company offers guarnatees that items will work months down the line only that they are as described on receipt.
If bought from a UK registered business, who offered some sort of guarantee that they are now not upholding, Trading Standards, and Citizens Advice are your next move if you wish to take this further.
