Cheating By Plot Agent, Cash Transaction

We got cheated for the amount about 8 lakh in the plot case by an agent. He never allowed to meet the owner and took a lump sum amount in cash. Later he rushed us to make an agreement of cash transaction which he never allowed to finish. So we have left with no evidence of transactions except call recordings where he has accepted that the mentioned amount is given to the owner through him. He had made an illusion that the plot belongs to a person relative to said owner and he is making transactions on behalf of him. After this case when we demanded money back he lured us in plot business in partnership. After a few years, he gave us a blank cheque but in hope of money getting back, we never used it till the date. The cheque doesn't mention the date on it. Later we got another person who said he will help us in this case. So we showed him, agents, home. Later he took one cheque from the agent and said to us that he will file a case against the agent. He filed a case on his name (not us) and now he is not paying heed to us not receiving a call