School Chairman Not Giving My Sister's Xii Board Certificates

My Father used to work in the same school where my sister did her Xii Board exams and he was a Business teacher and also used to do clerical work, he used to collect uniform fees and paid for everything with records but the Chairman held his 40 days worth of Salary. Now that my sister went to collect her Marksheet and Migration, she told her that there's a Bunch of money that is due on my Dad's front which is an utter lie, although it's her who didn't give my Dad's money. Please help.