Subway complaint: Fired my daughter via messenger while at school

My daughter has only been working at subway for one pay period and they messaged her today at school to tell her she wasn’t cut out for the job my first question is why message her why didn’t they talk to her in person also why did they message her at school to get her all upset at school also she was never told or wrote up about anything that she is aware of and she was just getting the hang of the job and really liked and enjoyed it there and when I contacted them about the situation I was spoken to rudely because I told them they were cutting out due to them being on their cell phone and was told all of these things when they were never brought up to ,y daughter she was always on time and even took extra shifts to help out but she gets done this way no call for it at all and you all wonder why you can’t get good help or keep good reliable workers in a time when workers are needed so badly no wonder people don’t want to work when this is the way they are treated