meddling parents 2

She couldn't find her exercise book. I told her to re-do the exercises from day one if the book is not found. She complained to mummy. Mummy phoned school; said the daughter lent the book to the daughter of a prisoner and the girl lost it. She asked how can the school take in the child of a prisoner? Then she voiced her disagreement with my punishment. Sigh........either she leaves my class or I leave the class. Will not tolerate with such interferance anymore. Same girl with the dancing problem!!!