How can i get this person out of my life?

I don't understand why your ex has to be in your life at all anymore! Usually an ex is an ex and unless a child is involved,that part of your life is ended! I'd say cut all contact,no matter what,and if that can't be done,then treat her like she treats you! Some people just don't deal well with nice and trying is a waste of your time and energy! She's getting a kick out of causing you guys all this chaos and you're feeding into it! Since being nice and acting mature isn't working,treat her exactly as she treats you!