MakeMyTrip India — Flight cancelled by airline but refund not given

I had booked two flights through MakeMyTrip, one on the 4th of January 2021 from Bangalore to San Diego flight no. AA-6656 and the other on the 15th of June 2021 flight no. AA-1939.
The first flight from Bangalore to San Diego was cancelled by the airlines (American Airlines) but my refund has not been processed after months. The amount was quite substantial so I hope I can find some assistance on this issue.
Tanish Alur