Athena - Bullying

Why is it difficult for parents , schools , teachers to do anything when bullying happens?

I think its difficult for parents, school and teachers to do something when there is bullying happening because sometime you might not know them. Like if its cyber bullying you have nothing to do about it because they're talking from a computer instead of in person. If it is bullying at school it might be difficult for them because the bully might not be telling the truth and might be threatening the teachers as well  The reason why it can be difficult for them because they might not have any permission to touch them and do anything to them.