Should I pay renewal brokerage after 12months?

Respected Lawyers, I have been living in Andheri west for 15 months now and I have an agreement with the landlord for 24 months. During registration I payed 1 month as a brokerage fee to my broker. Now he is coming back saying you pay me what ever you can as you have completed 12 months. He claims that he did not ask me 1.5 months as brokerage few during registration and I have to pay him brokerage now after completing 12 months. I told him I will be vacating the place by the 16th months and sent him away. I know for sure that brokerage is payed one time for finding and registration of the flat anywhere in India. He claims that its a norm in this area (Andheri west) that brokerage should be payed. I failed to understand why a brokerage should be payed for no job of his. Also his argument is if I had vacated the house, he gets a new party and is able to get the brokerage. He claims that this is a practice here. Please advice me on what I should be doing.. Its a pain that these guys create rules for themselves and monopolise the market by doing this. Regards Bharath.