Track the cun*s down with the trusty crowbar and 'clava and go get your money back! But to be honest I dont think there is any legal way you can get it back if there was no written contract between you. So thats is the only other genuine way to get it back... Rip off all the bumpers and trim you painted.. Or go one better.. Rattle can it a different colour at night, wait for him to ask you to respray it then tell him to do one!