A friend has emotional hurt me.

I need to vent and I'm not sure where to turn. My best friend is getting married. Her closest friend from college was her Maid of Honor. They got into it and her friend was demoted and she made me her Matron of Honor. Her Ex Maid of Honor has shown me screenshots from their conversations about my best friend saying stuff like "She smell bad" and some more really horrible things about me. This girl was MY BEST FRIEND. I'm so broken I don't even what to talk to her about it. Advice? Thoughts? Thanks Ladies