Well, in your position, I would have let the seller know that it doesn't work, and let him respond.
In most cases, this will sort things out. The good thing about ebay is that it will step in a help you, if you raise a dispute, although the seller should know that he really doesn't want to get a bad name on ebay.
I have bought 100's of items on ebay over the years, and have never had any trouble, although I should point out that almost all of the items I have bought, with the exception of second-hand books, have been new.