Never ever, ever...ever give a mean person power over you! It can actually suck the life blood out of you and if it goes on long enough you might, unintentionally, become exactly like them. Garner the strength, keep your self-respect intact and walk away...this may just put that mean troll right in their place or sad but true, they just may move onto their next 'victim'! Be at peace that you made the right decision for you.