Questions: Education & Career

I'm gonna try and make a long story short so just ask for details if you need them. I'm a full time student with two jobs and unfortunately one of my classes is on campus two days a week. For a bit of background my shitty morning job is like a high school clique. It's a shit place where they bitch about the hours and expect you to do 100 things for shit pay. Also did I mention that they only promote bitches, assholes, and jocks, who don't work, just because they're good friends with the boss? Yeah.

So this is the only job were my schedule is in conflict, my good job is in the evening (I love my other job). Anyways back to the point of this post.
I asked my shit job if I could switch my two off days to the days I needed or if I could just take less hours and free them up for someone else since apparently we're running low. My boss got pissed and went to her boss and they both wasted like half an hour of my time bitching about why these couldn't happen and trying to put it on me having a second job 😑

First of all I'm allowed to work where I want, and second of all these people are full of themselves. Your paying me shit
Pay for more work and you refuse to make me even full time but I'm supposed to be loyal to you? I think not! The only problem is that I lack a car and I need one badly. Any suggestions? Thanks