highalert the problem is though, it's hard to take seriously an OP who is given half a story from her daughter, then only tells us part of that story on here - who then writes to the Head Teacher.
Teacher's would not dismiss a genuine actual concern. But I can guarantee that the HT in question is dealing with kids that are causing issues such as: physical violence, verbal assault, teenage pregnancy, neglect at home, safeguarding issues, exam stress, parents not giving a shit, truancy, missing pupils, police enquiries.
All this as well as trying to run the school on a day-to-day basis. With public exams, lessons, trips, truants, cover, schoolwide events etc
There was clearly more to the story than what was told. But the parents phoned into complain anyway, without finding out what actually happened.
So YES, the other posters are taking the piss out of OP. teacher's included.