i would firstly kill the idiot who ruined your car then sit back and see how you feel after that,
you may find that thats all the satisfaction you need
:P
i always take a photot of my panels before it goes into a dealer nowadays, then f they dispute any damage i would pull out the pics which are dated, never needed it yet hope i never do.
always walk round and point out any damage, they write it down on their checklist at service and its confirmed before u leave, a bit of a pain i know but its the only way to cover yourself nowadays, it also covers them for customers claims.