How is it lawfully wrong? The transactions happen between the auctioner, the owner of such items, and the bidders. Ebay only takes responsibility for maintaining the site and providing a way for the people to exchange items.
As you said you must be an ebay member in order to complain. However there is nothing lawful you can do to them because when you sign up there's a little something that you have to agree to called the "End User License Agreement."
You, the end user, agree, among other conditions, that ebay is not responsible for auctions that are horrible or wrong. This came up when a man put up for bidding a night with his wife. I think Ebay stayed safe in this but I don't know how it turned out. All I know is some guy got gyped on his bid.