I see this is an old post-but perhaps my response will be useful:
My answer to your question is going to be quite similar to most, and that is read the terms and conditions for that auction company. In order to participate in a Proxibid auction, a bidder must have read and then agreed to the terms. It's a legally binding contract between seller and buyer. If you back out on something you purchased, you can be sued. First, I would contact the auction company and see if they will let you out of the sale. There is always the possibility. Second, if you found legitimate information that they are fraudulent, or something of similar concern, you might have a leg to stand on. I would share that research with a member of Proxibid's risk management department. Has your credit card been charged? If not, you may want to put a hold on it, until you figure out what you are going to do. Do not delay in contacting Proxibid, as the auction company may report you to Proxibid for non-payment and you will be black flagged. This means you may lose all your bids on other Proxibid auctions and lose the ability to participate in other auctions until the black flag is removed. Lastly, perhaps everything is fine and the items you won are a success story for you. It's been awhile since you posted this. Hope it all worked out!

Hi, I just won some articles on proxibid with governementauction.com. After the closing of the auction, I made some research on governementauction.com and their appraisal company and got afraid to go forward. Is there's any way to back step on the transaction?