How does one bid by mistake, when you have to fill in the amount, click" bid now" and click a second time to confirm the bid ??? Sounds more like he changed his mind !!!! But whatever happened , he can cancel the error bid !! You can ask live help how to do that" I have never done it" !! He would not get a negative unless you gave him one !! Ebay has nothing to do with that !!! A problem has to occur and someone has to complain before they get involved unless its a breach of ebays rules !! At least that is what they told me !!! Everything after the auction is controlled by you & the buyer !!