Make my trip - Airline refund paid completely unethically

I booked * Air ticket * & fro for Mumbai Dehradun. wherein Rs.**** Air ticket charges to go and Rs.***** Return Ticket charges and Convenience Fee with GST Rs.**** was charged on which Rs.**** Bank payment discount was applied and I paid total Rs.*****. Wherein the flight to go was cancelled by airlines sending a refund note of Rs.****. Here Makemytrip deducted Rs.**** Bank payment discount and only partially refunded the amount Rs.****/- here they not even recovered Bank Discount which was applicable on the return ticket as well plus the convenience charge for the flight cancelled by Airline was recovered. This is clearly an example of making money unethically and recovering money for the inconvenience service, taking the customers for granted.