She has been a nightmare recently. She's attacked her fiance, fell out with our parents and cut contact with her children to use against them. She's very volatile and you feel you tiptoe on eggshells around her (yes I'm guilty of this too). I've distanced myself from her since she admitted physically being violent to her fiance. Apparently this isn't the first time either. She has bad anger issues which I think stem from bullying but that's no excuse.
So it started from when she told me about the incident. I was in the middle of arranging a get together. It was on fb messenger which Dsis doesn't have. I was texting her the details though. She got annoyed it was spoken about without her but told her she doesn't have messenger so that's why and I wanted her to come along. She then set me messages saying everyone in her life is self centred, she isn't the problem everyone else is. Didn't speak to her for a few weeks.
I then organised my birthday and wanted to go to an event. Asked if her and her family wanted to come along. She said yes and paid for the tickets. This was a week ago. Then i text her a few days ago asking if she was around and would be nice to see her and my nephew. She replied just with "No". I said oh OK, how about tomorrow. Again "no". I asked what was up. She ignored me. Today I asked if she was still coming Monday and I get "yes". That's it.
Now I'm worried she's going to ruin my birthday with my family by being a certain way and making it awkward. I don't really know what to do. Part of me wants to say if you're going to be this way I'll refund the money and sell the tickets on....