No idea what this encounter was about, but I second the view that your priority here should probably be fixing the drive train on your bike before you take it out again--when I rode in New Orleans, there was more than one time where riding fast got me out of trouble, and riding a bike prone to breakdown is generally asking for all kinds of trouble (safety from accident as well).
Over the years, I've had a couple of situations where someone has attempted to mug me, but they were on foot. It actually was kind of pitiful because there was no way they were going to get me unless I was stupid enough to let them corner me. Last time, they actually told me to "Hey! Come over here!" in a threatening-sounding voice while they were standing next to some bushes in a park. I resisted the temptation of asking them if that ever worked and rode on.
Another time, a kid tried to put a stick in my spokes while I was riding in the street (I think he wanted the bike). Turns out you don't even consciously have to know that's happening before you swerve to avoid by reflex.