In Second Life anyway, I find the mute button an extremely helpful tool. I also have a private piece of land that I can ban anyone from should I choose to. A refuge if you may. I know this is not always an option, but I would change who you talk to, and where you spend your time. Ignore them as well. They seek attention, and like a 2 year old thowing a temper tantrum, if you ignore them, they should stop. Just some hopeful suggestions.