Stop payment cheque case defence

Dear sir/madam. I am satish, I had run a Franchise-trading office for two years, the head office- MD closed the Trading office without Intimation on 18-AUG-2015, and four clients were suffered during this. In this panic Situation i gave 4 signed chq leaves to four clients only mentioning the amount without date and name as security of the invested amount on 21-AUG-2015. 10 days later the MCX and SEBI initiated the actions and proceed for arbitration. so i give all the cheques Stop payment under head "Cheques lost". MCX Arbitration panel with Retd Judge Mr.Sampath, pass the orders in favour of invested clients and they told in oral that they will send chq to the suffered clients in 3 months. Now three clients accept this and return back the cheques but one client refused to return Chq , he presented in bank within 3 months and files the case under negotiable act 138 saying that i took liability. Trials in court start next month. i didnt send any reply notice to him, and also i didn’t get any signature from him while giving the chq. The cheque amt is 114500/- I gave cheque amt for full invested amt of rs. 114500, but while applying for claim amt rs.68000 is mentioned which is as credit balance of ledger as per oral instructions by MCX, so i am unable to prove both amt is for same purpose, but i have proof for invested amt of 114500 to trading office by him Please give me some suggestions to defend this case.