My boss changed my shift 3 days before it was supposed to happen and turned a 9 hour shift with a 30 min break to a 10 hour shift with an hour break. Mind you this is at a coffee shop. We’ve been so busy and they don’t want to hire another person.
Your boss is an asshole. Once the schedule is posted, every change after that should be voluntary. Even if it's only a 1.5 hour addition, you shouldn't be forced to just accept it since it was made after the original posted date.