I have a girl child of class 9th .Her father brings her up and is a divorcee. He is usually out on his duty but his daughter, in his absence, steals away a lot of money from his pocket and buys harmful junk food with that money. One day my class students told me that she daily brings such stuff, costing approximately 400 to 500 rupees ,daily with her.

To my utter surprise, when I checked her bag it was full of eatables.I called away her father and brought the matter in his knowledge. But ,he seemed very helpless and could not find a proper solution to this problem as it has started happening sud to her mother's absence. Even I tried to counsel her but she seems to not have much impact of my words..
What should I do next to modify her behaviour and habits?