confused about friends

So basically me and my friend Lexi have had plans for the past two days and she will pick up other people like one girl named Liz and Liz hates me and my friend well end up blowing me off because Liz will tell her to do stuff and Lexi listens  and Liz  is  using her for her car and I've tried telling Lexi  but she doesn't believe me or she'll just say whatever and blow it off but I feel like I'm losing my friend and I don't know what to do