I (19F) recently got a job about a month ago. During the hiring process, I made sure to read through all of the paper work which never said overtime was required. It only said overtime is possible if you request it and get it approved. Of course I could've verified there would be no overtime but I was told all of the information I would ever need would be in the paperwork. Well, last week my boss sent out a message saying This Thursday, everybody would be required to do mandatory overtime for an event. I explained to her I was never told there would he mandatory overtime and it wouldn't be possible for me to make it. She claims it's in the paperwork. I read through it again and told her it isn't. She says she's sorry i didn't get the updated paperwork and I still need to attend.
What should I do? I babysit directly after work and told the lady I babysit for she wouldn't ever have to worry about me canceling unless I was sick. I even told my boss I'd never be able to work outside of my scheduled hours but she says I'm still required to be there.