Maybe someone around you feels that you are in danger and need help. In such cases, the person can report this to the KESB (Child and Adult Protection Authority). They then file an endangerment report (Gefährdungsmeldung). These people may be friends, relatives or neighbours. But teachers and doctors can also contact the KESB.
If you need help, you can also contact the KESB yourself. You can go in person, call or write an email or letter.
In the event of such a report, the KESB must clarify that you are really in danger. There are very different ways of doing this. Maybe someone will first talk with you alone or together with your parents. In some cases, the KESB may require more information. Then, it is possible that someone will talk to your teacher. They may also require an expert opinion. The KESB must make every effort to find out how they can help you.
Perhaps the KESB understands that you are really in danger. They will then initiate child protection measures. They will explain to you and your parents what is being done. You may receive family support, for example. Or your parents may have to keep to certain arrangements and rules.