I'm saddened to hear that you've been tormented like this, as if just trying to get from day to day isn't hard enough already.
It's very distressing to be targeted by scammers like that, combined with the fact that they've been leaving intimidating messages on your machine is just disgusting.
It's sad to think that these criminals are totally devoid of a conscience. But then again, if they did have a conscience they probably wouldn't be scammers in the first place. I'm in full agreement on the karma aspect, and hope it returns to bite them in the ass, preferably when they least expect it.