Make my trip - Discrepancy in refund

I have booked a flight ticket using Makemytrip portal for **-May-** by paying an amount of total Rs *****, but due to travel ban, flight gets nonoperational and my ticket was cancelled by MMT on **-May-** and i got a confirmation of cancellation and refund on **-May-** with a refund amount stated as Rs. *****. I have asked regarding this reduction in refund amount with the same concern but havent got any reply, moreover on **-May-** i have received a refund in my account of just Rs. ***** which is Rs ***** less than what i have paid at the time of booking. Since then i am asking MMT for this discrepancy but i have not been provided with any valid reason even though i have received an invoice of cancellation by Make my trip which mentioned an amount of Rs. *****. Its already been **-** days but i am neither getting my balance refund nor any valid reason for the same.