Ines I do not know if her mother is married, but in my case I would talk to authority figures about her mother, grandparents, or boyfriend, and bring it up.
well, @Christine is very financially dependent, I don't think it would do any good, she would have sexual freedom but no roof over her head. Besides, you can also simply break open a belt, so that shouldn't be the problem.
I think it would be more important for you to find someone to support you until you are (financially) independent again. Is there no one else than your mother? if yes, then ask that person for help, break the belt and that's it.