That's awful, I mean how on earth would all that sh£t thrown on the car cover anything up, nobody's car would be that dirty on the front unless it hadn't been cleaned for 2 years I can't believe how they could do all that damage and just deny anything happened!

If I were you I'd print some pictures off from before and after, if you don't have a printer go to the local library etc don't clean it or try to fix it, leave it like that until they pay up