I hate my fiances family. what do I do?

So my fiancé and I have been together for a year. We live together and don't fight at all, our relationship is actually amazing. The first day I met his family, they warned me about his ex. How crazy she was, how she needs medicine, etc. so I'm like Jesus I'll stay away from her. Then a week later I'm told by family members she was going around saying I was threatening to beat her up when I had never once talked to her before. So I messaged her and it started constant fights because I know she is still in love with my fiancé, as they were together for 5 years. The family has told me they believe that too. So she's dating my fiances ex BFF, who is still my fiances brothers BFF. So her and her boyfriend are always with my soon to be brother and sister in law. Then they proceed to bring the ex around the family. She is constantly trying to get under my skin. Always posting things on social media when she is with MY family, to prove to us she can be. She even had the be ere to tell me no mater what I say or do is going to change her from comin around. She also calls them her second family even though they tell us they don't like her. She calls our grandma her grandma and lies about being at her house. She calls our neice Her Neice, and her goddaughter when she's neither of those things. She's constantly posting about us on social media and driving past our house, we had to move because they moved right next to us, and they somehow found out our new address and drive past this house too. She has managed to make our life hell. She is the worst person I have ever met. Yet the family keeps her around, invited her to dinners and our cousins birthday parties knowing she only comes to upset me. The family hasn't even tried to get to know me, and recnemty it has 100% destroyed our relationship with his side of the family. I flipped out on his mother, I was extreamly rude but wth valid reasons. We just had to go to court against my fiances ex and her BF to try and get a restraining order but the judge wanted nothing to do with it so he denied it. I would think that my fiances family wouldn't want around the girl who made my fiancé want to die, and cheated on him with his BFF at his own brothers wedding. But yet they keep her around and now we're not allowed around. What in the actual fuck am I supposed to do? This bitch thinks she won and I refuse to let that happen.