MY ARTWORK FOR 'MIXTAPE' LOGO WAS STOLEN

I DID THIS LOGO FOR "MIXTAPE" COMIC SERIES OF MINE (BACK IN 2008) t-drom.deviantart.com/art/Mixt… AND SOME MONTHS AGO A DESIGNER CALLED EDWIN SERVAAS STOLE IT AND SOLD IT AS HIS WORK TO A C...LIENT > edwinservaas.com/2009/09/innoc…
(+ HERE > www.innevents.com/about.htm )

ANY HELP HOW TO DEAL WITH THIS ???
I ALREADY SEND AN E-MAIL TO HIM, HIS CLIENT AND TO MY LAWYER...