I concur feed back is important as the number of sales of the seller
If you have an issue with a buyer, you can contact GB support via email and open up a support issue. They will contact you back in 24 hours.
IMHO, phantom bidders are nothing more than GBs proxy bid system at work.
I have made some unbelievable purchases on GB simply because no one else bid on the item.
Also, like I mentioned in a previous post; there have been many instances where buyers would remove or replace parts from a firearm and send it back.
Non paying bidders are also a problem.