Most likely a shill. I've got the same problem. You aren't going to get any info on them until the auction ends and eBay won't divulge any info till then. The only way to stop them is to relist and before that block that buyer. This is going on a lot right now. A lot of sick people out here and eBay once again won't do anything. They'll end up not paying but eBay will still allow them to repeat the same **bleep** again.
There are a lot of cunning individuals that can create fake eBay accounts very easily and eBay won't ever find out till the worst is already done at your cost. The legit buyers are forced out of the auction because these frauds are setting the bidding limits so high and they won't pay of course. Already happened to me this week. Again, eBay does nothing. Good luck
