Proprieter of a firm not returning funds & interest due
One of my friends introduced me to one of his acquaintances to start business. After some discussion, I transferred Rs. 5.25 Lakhs to the account he provided based on trust and goodwill, and did not have any terms in writing then. I realized I transferred to his proprietary firm (not the business we wanted to start). Due to reasons we did not align on the business plans to start business and my funds were held up in his proprietary firm. He also requested funds for his proprietary firm (to venture fully) with an interest rate attached verbally. He agreed over email to return funds after 4.5 months. Thereafter, he has given umpteen reasons (several unconnected ones) to repay, set and missed several dates. It has been 6 months so far, he paid Rs. 3.5 L (after several constant follow ups, unwanted communication and influencing thru' common friend) and one of his cheques got bounced once during this period. He finally set his own repayment schedule of the balance (had no choice but to agree to avoid legal costs, efforts and process delays - he sees it as advantage that he gets more than 6 months time to repay thru' legal arbitration) and including interest rate (though lower than what he initially said but had to agree to find a quick closure) in an email to which I agreed. It has been over 3 weeks and he has been giving various reasons without repaying. Also, now saying he will not pay interest (around Rs. 80000 so far) and tagging it to 'help' in loosely tied context which was never agreed by me. The email agreement we had clearly states it is 18% interest. What options do I have to recover (a) the amount that is still due and continues to skip (b) interest he agreed to pay and now saying will not pay (c) legal options including any penalty that can be levied, legal and other expenses that can claimed for pushing me to the option.
He has also indicated in the past that he could file a defamatory case for interacting with common friend (who introduced us) to influence him to repay my money.