Shall I pay three month salary as breach of contract

I was working at a private school as an assistant teacher. It is under our native political leader. I have signed the bond for 5 years. Within three months, I realized the reality of such an institute. Actually, they will pay their salary for 11 months. They will not pay their salary in the month of May. I accepted that condition also, but in the month of September, they deducted 2200 rupees without any prior notification. When I asked about that, they told me that this is school policy; we will take a half-month salary as the liability of an employee. But it was not mentioned in the contract. I got information that next year, i.e., in 2024, during election time, they will deduct one month's salary for political funds. When I discussed it with the school principal, she didn't give any reply on it.In the school meeting, they declared that they would only take half their salary as a liability. It is highly impossible to give a one and a half-month salary from an 11-month salary. So I left that school, and recently I joined a new school, but the previous principal called our school principal. She told the principal, "Mam, tell him to pay a three-month salary". Our principal, Mam, discussed this matter with me. I am really facing financial problems. They are telling me that they will file a case against me. What should I do?