Cheque misused which was given for security

Hi Sir, I have subscribed to multiple chits with one person. I have paid the chits amount regularly through online to give bank account (the account number is not belonged to the person who running the chits. But as adviced by the chit person by email we have transfered the amount). The chit was completed in the year 2015. Finally we have some due on chit amount around 4laks. The same was chit person sent an email to us with the attached statement which is showing pending amount. Due to some financial crisis we have not paid due amount. Finally in the year of 2017 we have agreed to pay him 6.5 laks including interest and given promissory notes and post dated cheques. Meanwhile we have paid all the amount 6.5laks through NEFT transfer to his own account number. After that chit person deposited the cheque and same was bounced, he issueda legal notice to us. Then we have given replay notice stating all the facts. But he is filling the case against our family members. Can you please what'