Sort of the same thing happened to me a while back. At a stoplight, I was in front and buddy behind bumped into me. It was just a nudge so I didn't think to much of it (my car was old) so I just drove off (I was going to the bank about a block away). Well this guy starts following me honking his horn. I pull into the bank with him right behind me.

He jumps out of his car and says I rolled backwards and hit him. Right then and there I smelled a shakedown so I said you wait right here while I go and call the cops. Soon as I said that, his buddies (he had two people in his car, I was alone) say let's get going. So I just laughted at him and went into the bank.

Punks.