Max Bupa — refund

I have purchached a health insurance bearing policy no [protected] but due to poor response from the insurer i have cancelled the policy. As per the details provided in the policy for termination grid as i have paid rs 10000 for premium the amount to be refunded are as follows
Effective date of the policy:-11/03/2019
Receipt of cancellation request:-07/04/2019
No. Of effective days:-27
Refund applicable: - 87.5%

My health insurance policy been active for 27 days and hence the refund applicable for policy # [protected] is rs. 8750 /- (Approximately).

I have paid a total amount of ₹10, 000 online on 11/03/2019 (Via payment link rs.10000/- (Ref. Id:[protected] as premium, so the refund money applicable as per cancellation grid of 87.5%, is ₹8750/-

But after a long discussion and debate with the customer care executives for almost 2 months, max bupa had refunded me an amount of rs 2261 stating that they have recieved the premium amount of rs 2584 only.
I have given them all the transaction details including bank statement of paying rs 10000 but the didnot refunded me the correct amount. Now the are not responding.

Kindly help me for getting my money back from such a fraudulent company.