A land broker cheated money and not returning

I'm NRI. I did one land deal in which as per agreement I transferred money from my NRI account to land broker (mediator) SBI account around 43 lakh which he received in written and signed on agreement. Though he falsely mentioned over phone and whatsapp message that he was transferring all money to land owner account however he never passed that 43 lakh to land owner. Hence Land owner is not registering land and asking for balance money. And that broker is not returning money to me and failed his all promise to pay back for last 5 months. That land broker belongs to SC/ST (chamar) and threating that he is recording all our telephonic conversation which I'm doing with him in order to asking/requesting for my money. Sometimes we had a heated discussion in which we used abusive languages. He has been torturing for us for 5 months in which he has been failed his promised date to payback. I'm feeling very helpless and mentally, physically, financially tortured by him. Please suggest how I can take legal help in order to get my money from him.