How to file complaint against business centre for unethical practices

Hello, We would want to understand how we can file a complaint against a business center in chennai for following unethical practices regards to referal bonus to its partner for commission. We referred a client to regus samson tower and as per oral commitment we were supposed to get 10 % of total business value recived to them from referral client. I am also a client of business chenter chennai and General manager had commited me saying as client you would recieved only vouchers worth 15K and real estate broking company you will recieved 10 % of total business value in which case workd out 60 K. So i had given details of my other company which is in to real estate and finance brokerage to register with them as partner. Now the general Manager after client had signed up its denying me 10 % of comission and instead offering me 15k Voucher. Please update on this scenario how we can complain against this unethical practices.