A case of impersonation

Was scolded (or informed if you might say) on Twitter few nights back, that I was stealing others' works and posting it on World Cosplay.

First thought that came to my mind was, "I only have a General Member account on World Cosplay, which you can't even post photos.", so how the hell am I able to post photos?
Secondly, and of course I don't steal people works.

Saw the link that person gave me on Twitter, and wow!
Someone is impersonating me on World Cosplay, stealing MY photos, and OTHER PHOTOGRAPHERS photos, and posting those photos online USING MY NAME

The stealing part is already wrong, to me and the other artists.
But posting it USING my name, is blantanly trying to malign me for something I didn't do.

I have sent an enquiry to World Cosplay, explaining this issue, but till now I have not got back any replies.

So just to make it clear, I only have 1 account on World Cosplay (which is a General Member type, and can't post photos).
My account: worldcosplay.net/member/766/

The person impersonating me (fake account): worldcosplay.net/member/57624/

Hope this explains things, or someone is able to help me with this issue, will be greatly appreciated!