My bestie sense 5th grade is consatly lyeing to me and will not admit it then gets piss off and not talk to me even if she's at my house or in public?

She is either a compulsive lier, or she is not your bestie any longer.

Tick

OK if she/he was a good friend, none of that would be happening. You're not doing anything wrong and if things like that keep happening, maybe you're better off without that friend because it's not really worth it

Thanks but how do I tell her she's not my bestie?

I think you should do something nice for her first. Just the two of you to get her in a good mood. Then, you tell her about the problems that you guys have had because she lies all he time and tell her that if the lying doesn't stop, you're not going to be friends with her anymore.