Avoid A Broker In A Deal

I have seen a property through a property agent, he introduced me to the seller, but the deal was not finalized due to our restricted budget. Later it was come to my knowledge that the seller is a good friend of my office colleague. My colleague talked with him and he agreed for the amount which was under our budget. Since the deal is now finalized, the property agent is coming to the picture and asking me for 1% brokerage. He is threatening me that he will file a cheating case against me if not paid. Please guide me that whether I have to pay him brokerage charges and whether a case can be filed against me for cheating. Please guide Sir.