Once your car gets repaired, keep an eye on it because the person who did it may not be done with your car!

If you did pi$$ someone off they may be so pi$$ed off at you, to wait till it was repaired and do it again!
Perhaps get an alarm installed so you know when it happens again and can chase the person down like the dog that they are and put a beating on them!
Also, if you have a video camera, set it up to film your car for a while and you may get lucky and catch them in the act!
One good thing may come of this, your paint job will be new!
Stephen