Shriram Life Insurance Company — delaying my outstanding payment

Address:

Chennai, Tamil Nadu

Policy taken and returned back with in a week for repayment of my first premium paid amount rs.50000/- since i am not happy with their terms and condition and maturity returns amount.
January 4th 2019 i sent back the policy instead of repaying my amount they unnecessarily avoiding payment and re sending the same policy to my address with back dated covering letter.

Please suggest what action we can take to get back the amount with interest.