Private money lender is threatening to payback Very high interest

Sir I have borrowed 5 lakh from one of Private money lender in Mohali (Punjab) ALL IN CASH. Verbally the interest rate was 11% per month which makes it like I have to pay 55K per month as Interest only. I case I got late in date of payment he charge 5500 daily. Totally If I calculate I have paid around 22 Lakhs Only Interest till Now. I requested him not to charge any interest now and I will pay the Principal amount in next 10 months. He is not agreeing on principle, he want all his principle + last 4 month interest + late fees charge which makes it 24 lakhs again. That conclude that I will pay 46 lakhs n principle of 5 Lakh (actual one) But he did not agree, he has put my 2 cheques in account for 12 lakhs each. Here is some points. The amount he paid to me 5 Lakhs is all cash .. no bank transfer I have paid around 7 lakhs in his account and other I have paid through cash withdrawals from banks. Cheque will be bounce in couple of days. what should be done?