Dishonored cheque case

Hi Experts, I was part of a team of 6members (3 from delhi, 3 from mumbai). We executed a food festival in Delhi. The execution vendor was introduced by me (i asked for INR50k as commission against giving him work and he agreed to pay). Before the event every member was considered as partner though no partnership deed was signed. We were communicating through conference calls, whatsapp groups and a common Gmail account. The event came out to be a flop, we were in losses, each INR 4lacs as the cost was INR 24lacs. Some of us invested money to pay advances to vendor, one of us didnt invested any money. Next day of event 2 members clearly said no to the partnership and not to bear any losses, one of them was a girl who tried to threat us as we are harassing her and asking money from her. One met expenses of 3.40lacs and never called back. One arranged some 13-14 lacs and paid to creditors and vendor. I took loan and paid 3.50lacs to vendor and told him to settle my commisiion against the remaining money. One member who brought all of together has vanished, not responding to my calls. The vendor has to be paid now 1.70lacs more. I given him cheque of INR 1lac as security, but after 2months he deposited in bank and it got dishonored. He was aware that there is no balance in my account. I paid him 40k and told abt 50k to settle against my commission, but he deposited again my cheque and again it got bounced. Now he has sent me a notice U/s 138 of Negotiable Instrunment Act asking for whole 1lac. Please advice me how should i proceed. In my eyes i have paid him full money but he want me to pay him more than my share.