Or you can call the local complaint number and report the situation to the Education Bureau. You can log in to official website, the local education bureau, and complain online. You can also write reports.
Complaining about the consequences of school. If the complaint is true, reasonable and legal, and justice is on your side, then don't be afraid of anything. I believe that the higher authorities will give you an explanation, and the school and teachers will not take you seriously. If the complaint is false and illegal, you will be criticized and educated, and if it causes serious consequences, you should bear corresponding responsibilities.