Wronglfully fixed u/s 138 of N.I. Act

Sir, I did certain work for one of my client in 2010 against which he paid me by cheque Rs. 12 lakh. This was against the financial services and other sub contract work i did for him then. My client is a stock broker. Further in 2012 i gave him cheques amounting to Rs. 6 lakhs (3 cheques of 2 lakh each) as an advance (margin money) which is required for doing F & O transaction. But without even opening my demat account and me executing any share transaction, he put the cheques for clearance with my bank. On being informed by my bank after clearance of first cheque, i immediately stopped payment of the remaining two cheques. Thereafter he filed a case against me u/s 138 of the N.I. Act. The case is still pending with the magistrate court. He is contending that the cheques relate to 2010 payment made to me. I dont have any document proof which can proof that the payment was made for the work done to him and not loan. However he also doesn't have any loan agreement made between us. He has produced a fraudulant statement of accounts showing the liability in his books but the same is not signed by me. Kindly guide on how to get out of it. Thank you.