What to do is Email Ebay tell them to stop asap.
Go to google and you will find a trademark form somewhere and you need to fill this out and send to google and google will stop anyone else from advertising your trademarked terms (in the title of the ad).
Now I've not made any complaint and Don't concider this a total breach of my rights although it uses my business name to try and reap traffic from adsense and search users, I'm not happy to see 'search for -my-site-name- on ebay' just because of a dealship google and ebay have made, I could understand if ebay genuinely feared me as a competitor but I don't sell products and I'm far from competition to ebay... so I call this cheeky and therefor have to tell the public about this, despite it being done I wont take any action.
We've all seen google adsense mess up but this is surely wrong in all aspects I believe it is to be Illegal and should not be keyword automated as I've seen.