Restrain him firmly (Oh did I break that?) until the police arrive. Get him in court and get restitution for the damage. Voted for Beat him to a pulp. I once left a friend to walk after he slammed my doors. He understood and is still a friend.
Good - Fast - Cheap: Pick any two.
E23 735i; E32 735iL (X 2 - 1 Alpine White and 1 Glacier Blue); E34 535i; E38 735iL; R50 Cooper; R55 Cooper Clubman.
E21 318i; E30 318i; E32 735iL; E34 535i; E38 730iL; E53 4.4i