Hoarding License for Advertising

One gentleman - a so called Corporator - did nothing to help me in getting the license for more than two years. I was made to run from pillar to post. However, I kept on sending written reminders & personally meeting the C.E.O. every now & then, as I din't want to pay any bribe. Finally a license was granted to me after much toil & waste of time recently. To my surprise the said corrupt Corporator demanded a huge sum stating that he has facilitated the licensing. The minutes of the board meeting show to the contrary. Now this gentleman is calling on my Client telling him not to pay the Advertisement charges to me, but to pay the same to him. He is a "gunda" type & is spoiling my business. Can anybody guide me in this regard as how to set right this corrupt Corporator.