First off, let me say DO NOT mention any names or link to any sites so this thread doesn’t get locked also.
There out there, stealing your themes and you can easily find them. They have Facebook, Twitter pages and Web Hosts that will aid you in getting it removed.
I came across a site today that is offering hundreds of free premium Wordpress themes (including mine) and I hit their site, Twitter and Facebook pages with DMCA notices as well as emailed some of the authors with links to get as much as possible taken down.
You can find them, do your part and get these crooks shut down. Download one of the zip files and I guarantee you’ll find links to their social networks in a text file. All I had to do was search on Facebook using specific keywords and they even had a button on their homepage to their Twitter account.
Email Envato support with links and you’ll get a shiny new badge to add to ye treasure!

