The thing about buying passes on Ebay is there is no way to verify how many, if any days are left on the passes. Once at WDW you can verify the days but if there are no days left you're totally out of luck and the cost. WDW won't help because the passes aren't to be resold. Most likely, Ebay and PayPal won't be able to help either since there is a specific time period to make complaints of this nature. Feedback can be left up to, I think, 90 days but that doesn't really stop the seller nor hurt them that much.
ETA Lately it seems Ebay hoppers have been going higher (add in shipping) than what it would cost to just purchase the new tickets from WDW or a reputable dealer.