Honestly, the next time they bother you, I say video tape it, and look directly at them while video taping (perhaps a smile would be a bit more taunting) and from there either show it to the cops or put it on Youtube for everyone to see and title or accordingly so people can see how big of d-bags they are. If they want to act out, then give them a grand stage.
Sorry you had to go through that buddy. Even if you decide to do nothing, what goes around comes around.