Originally Posted by ArtPE
3.1 Online Auctions. Although we are commonly referred to as an online auction web site, it is important to realise that we are not a traditional "auctioneer". Instead, our Site acts as a venue to allow members to offer, sell, and buy just about anything, at anytime, from anywhere, in a variety of formats, including a fixed price format and an auction-style format commonly referred to as an "online auction". We are not involved in the actual transaction between buyers and sellers. As a result, we have no control over the quality, safety or legality of the items or content posted by users on the Site, the truth or accuracy of the listings, the ability of sellers to sell items or the ability of buyers to buy items. We cannot ensure and do not guarantee that a buyer or seller will actually complete a transaction or act lawfully in using our Site.
in other words, you're on your own...
In other words, the OP cannot sue eBay if the sale does not go through. Whether that precludes the OP suing the seller is another story, which our legal representation here
seems to think would be successful.