OK A lot of people are complaining about stolen stuff, but really, look at your uploads
you don't even write a copyright notice and rather leave the description blank as if its taken for granted.
So what can you do to protect yourself? you can start by editing your files and adding "Copyright © YOURNAME 2009 (or the year you made that specific item)
Secondly you can add license to limit the usage of your files (CreativeCommons license for example - http://creativecommons.org/
Now mobile9 wouldn't be responsible if another site stole your material (unless it's reversed as in someone posted a copyright material on mobile9) so this is all under your responsibility . you can contact the admins of that site and ask them to remove your material or at least give you credits else you can file DMCA compliant / copyright infringement and terminate that website AND if you need help with that, contact me and good luck