I think the Deputy Head teacher at my school may be bullying my best friend; Katie?

I think the Deputy Head teacher at my school is bullying my best friend Katie. She organised for Katie to show some people around school and Katie didn't wanna do it but she insisted. They had to be at a certain place at a certain time but Katie can't tell the time very well so she didn't know when to go. She didn't turn up so she got summoned to the Deputy Head teacher's office. Afterwards Katie told me that the teacher had told her that she was very disappointed in her and that she didn't consider her reliable or responsible anymore. Katie also told me that the Deputy said that she thought that Katie thought that she was a rebel. Which isn't true. Katie never get's into trouble for anything. And she only create's a fuss over something when something has really upset her. I'm pretty sure more was said, but that's all I know about. And I'm really worried because I think the deputy might be bullying her. So can anyone tell me wether she is or not please?