From your friends behaviour looks like she is still angry and is dealing with her emotions publicly. Don’t let it affect you. An angry person will only be spreading anger as they are thinking emotionally. It’s also sad that no one is supporting you. As someone suggested just mute the group and only wish birthdays. Don’t waste time on ppl who don’t value you. If you have done nothing wrong there is nothing for you to worry about. i too had faced bullying and being cornered out by a woman. She was not my best friend but she influenced my best friend to distance from me. I decided to stay away from both of them although wish birthday sometimes.