A question about Facebook messenger history

[SocialKings]

So basically my best friends (crazy) girlfriend accused me of sending her nasty messages over messenger. I don’t know why he believes her, she has no proof and I’ve shown him several things such as my phones battery history and the fact that I blocked her a long time ago (can’t show the date I blocked her) but he still won’t believe me. I don’t really care about salvaging things he’s a very bad friend but is there any way I can surely prove I never messaged the girl? Like a chat history that can’t be altered? – by /hq/23ninjas911 – –