Management at Taco Bell sucks.?

I work at Taco bell & the hiring manager is just blah! Their rules are ridiculous you can't clock in early if you come in early (understandable) I work the graveyard shift so I work from 11pm to 7am & I'm not "allowed" to clock out at 7 if my manager isn't here (which she is later everyday) but the othe rlady who works at 7 ALWAYS arrives 15/20 minutes early. I just feel like if you're a manager you should be early, in my opinion on time is late but I'd appreciate if she'd actually come ON TIME.

I left today at 7 & she called me & said that I need to stay til she gets there & asked why I left I said 'cause I'm scheduled 11-7 I have to clock in at 11 no time before then I have to clock out at 7 no time after & then she asked me to stay next time & I told her no & she said you can't wait three minutes for me. & I told her nope I can't (even thought she wasn't late 3 minutes she was late around 15 minutes which is early for her.)

IIm pretty sure that's against the law right? They do a lot of things there that seem sketch but I don't know how to go about it other than what I just did. Any advice for what I should do. I'm thinking about just quiting but I'm not sure