Moral of this story is to never give out your PIN. My company always does in house communications via PIN but that is where it stops. Email is used for everyone outside.
PIN messages while they can be annoying, as long as you have an unlimited data plan dont really do much of anything. if they are bugging you after you tell them to stop, you can report the harassment to your carrier and RIM but it is unlikely they will do much. on the other hand, you also have their PIN and following up with the Police might stop the other party from doing anything further. I am curious though, since BB Connect gives a software PIN if that can be changed. havent had a chance to play with BBC in quite a while.