Spending week with ex. Friend

So, there is this girl I have been friends with for a long time. We always hung out and then she stated being super rude to me and some of my other freinds. She says that I "ruined her life" and many other worse things. The weird thing is that it was completely random and I don't even know what I did wrong. Whenever I ask her she just responds with, "there are so may things you did wrong I can't even tell you all of them". Like what? Then she refused to talk to me in person and demanded that we spoke over text which made it extremely difficult because things would come across wrong. She continued to be rude and say mean things about me to other people. After texting for months we both declared that are friendship was over. So that was fine, yes I was upset considering we had been good friends for over 3 years, but at least now I didn't have to fight with her. Well shortly after this I found out that she would refer to me with the name Daisy (which is not my real name) so she could talk behind my back. Then when I confronted her (through text) she basically bullied me. Throughout this entire thing one of my other close friends was friends with both of us and felt like she was in the middle. Anyway, now it's been a few months and me and the friend who was in the middle booked a week at summer camp together. But now it turns out my toxic friend is going too and we are I the same cabin. I texted her asking if we could try and be nice for the week we are there, but she hasn't responded (and it's been weeks) I'm not sure what to do because I don't want her to ruin my week at camp... Any suggestions?