Someone with more knowledge will probably be along soon but from what I know a warranty on an ebay item is useless unless you've purchased from a seller who is a licensed dealer/seller of those items.
That's why you are better off buying expensive items from a bricks and mortar store rather than ebay. These boards have numerous posts such as yours from people who's items are now not working and who can't get them replaced or repaired under warranty.
If you are within the 45 day limit since buying the item and paid via Paypal you might be lucky to raise an dispute with the seller, but otherwise you are at the sellers mercy.
They have no legal obligation as far as I know to honour your warranty (unless they are licensed or whatever as I tried to explain before).
I have copied this from another persons post regarding problems with ebay items and any warranty. The reply is from a experienced ebayer who knows what they are talking about.
"Warranties are not honoured if the seller is not an authorised re-seller and there are no warranties on items sold at auction.
If the seller is a registered business, contacting fair trading in your state may be the only course of action.
Some items are better purchased at a B&M store to get a genuine warranty."
and another:
"as a general rule stuff that can break down (electrical items, garden tools, computers, phones etc) should ONLY be bought at a proper store with a proper warranty."
