So you obviously have a talent for this because when I had pics stolen I could not get them to do anything about it. Can you please explain exactly how you did it (what contact email address or link for ebay, how you explained it to them, etc.).
I think that this kind of information would help many people here to fight this kind of stuff.
Hit the "Report" link and youre then prompted to sign in
Enter the auction number youre reporting and then in the next section where you're supposed to report the auction the info has been copied from enter THE SAME auction number
In the description explain the problem with a clear link to the same pic from your site, and that you've contacted them and asked to remove with no success. In addition I always mention that as hand-made items, each helmet is unique so you simply cant assume one is like another