I was down that road recently and found it very difficult to get Ebay to do anything. So now if I have an item that gets high bids from a 'shady character' with no feedback I simply retract that bid with the reason 'unidentified bidder'. I think that after three attempts they can no longer bid. I emailed this one particular bidder and told him that if he bidded again I would report him to Ebay. I also told him that if he wanted to bid again he would have to use a recognized seller identification. He did bid again using a friend's ID but alas, was in the end outbid. Unfortunately there are bidders out there who have no intention to buy only to jack up prices.