Betrayer or friend?

Last year me and my sister finally had a really good friend. She was really nice and so pretty she had like a million bfs and her family had a good amount of money…we had a band with her and her sister, we got pretty succesful until she told us that we wer slowing her down in her singing career, and that our very constructive critism was mean and that we had no right to say that, so me and my sister tried choosing our words really, really carefully, but it still wasnt enough. Somtimes she really annoyed us in the way that she thought that she had a right to everything and we didnt. Her mum once was screaming at me for no reason, I mean trembling with rage screaming, I was freaked out, nobody had gone off at me like that. I hadnt actually done anything! Believe me I’ve gone over and over all the things I couldve done and theres nothing that was offensive! And it hurt me that our once best friend didnt defend me when she was right there! what was worse was that I had just lost someone really really close to me that ill never get over, and she knew, but her and our so called friend didnt care. Now our bands split up and me and my sis sing by ourselves and we sound way better. We try talking to her but she always ignores us, I sent her like a doller worth text basically asking if she was ignoring us, but she hasnt responded to that either. My question is, is she still my friend? Or is she just a sl*t??