For context im in college at the moment and working a part time job as a kitchen porter i get treat like shit while at work even though I seem to be doing the most. I have a zero hour contract but was promised at least 20 hours a week but now he's said if I don't come into today after he randomly texts me I won't get over 4 hours next week after I agree he deletes the message about the no hours and acts happy go lucky that ive agreed to come in this was my only day off and I'm already overwhelmed and he calls me in with a threat of basically no pay next week for a 12 hour shift im dreading it.