User Activity

If we can only leave positive or no feedback as a seller, how do we let the EBay community know who is breaking the rules by not paying? I have a buyer who won my auction, has been with Ebay for a month and has alot of sellers complaining about her n...
I have given a refund no questions asked as a product didn't arrive at the buyers address. It was only sold for $10 and mailed as untracked but feel like I could easily be ripped off. Is this happening alot with AusPost or some buyers?