Check bounce

My dad was came to Delhi with my sister because she had to go to Hyderabad after completing her banker training. I was in Delhi itself. On Sunday when my sister had a train off to Hyderabad, my dad's client called him saying that he will take only few minutes as had to talk something urgent and he was liable to pay dad as well for his services. Dad and me went there, and the client knew that dad had to go with my sister the same day evening. It was Sunday and most offices there was closed and in client office also one employee and the client himself was only present. He showed some papers and said to dad that he had done some cheating and need to pay 2.50 lakh to him. He showed some challans stating that dad had payed less. Dad is not an registered employee of his company, he just gives him advice. However he threatened us saying that he will not leave us until or unless we pay him and in few hours the train was gonna leave and first time in our family someone got the job. We had to leave quickly, so dad gave a cheque with the same amount to him from my sister's chequebook, bearing her signature. My dad,sister and me left after that. After few days we stopped the payment from the bank and the cheque bounced. He filed a case against us. We didn't file a police report because we were scared in doing so, we are a middle class family never had such issues so never thought we had to do so or it would help us later on. The challans were used for payment of taxes and the client told that 2.5 lakh less amount has been payed by my father. However father was never liable to do such job,he is not his employee just gives advice and helps him out. He is not registered anywhere with his company. We belongs to patna and he dragged us here to delhi. The tax payment was related to the client company. What are the prospects of our case defence? What should be done?