Property Related Fraud

My neighbor introduced me to an Individual, She said he is a mahad Agent and can get me a flat in Mahada Building in lesser rate, We Trusted the neighbor and gave him 2,70,000 Rs in cash, later on we came to know he is a fraud and requested our money back further he executed a Friendly loan agreement and promised me to return the money now its been 4 years he has not given us any money whenever we call he says he is arranging the money and will give us soon. Recently he gave us a cheaque and it got bounced we filed 138 Ni act case according to the friendly loan agreement and the first hearing is near. Now he is black mailing us stating that it is a illegal activity and you cannot file an FIR and in court the judge will void the friendly loan agreement. My question if i say this entire story to the judge, would he Void the friendly loan agreement ? How do i file a Police complaint of 420 & 406 because i do not have any documentary proofs like - (allotment letters or sale deeds ) but i do have the call recordings where he accepted that he cheated us. Please guide me on filing an FIR and about the story should i say it to the Judge or just say that he took a friendly loan and not returning it ?