Make my trip - Refund not received for cancelled flight 3 years and waiting

I had booked a return flight ticket from Bangalore - Tucson, United states for carrier Qatar Airways on Makemytrip. The travel date was April **th ****. The flight was cancelled by the carrier owing to covid related travel restrictions at the time.
The carrier then issued a credit shell to be utilised in the next * years which I was unable to and therefore had requested for a refund in the month of March ****.
I have since been following up with Makemytrip for my refund to be credited to me. I have clear evidence showing the refund has ben received by Makemytrip from the carrier, but I have not received this from MMT after multiple interventions.
I have spent several hours speaking to MMT customer care agents, explaining the issue from scratch, only to be promised a new timeline for the refund. The case then gets abruptly closed on the MMT system with no communication to me/refund not issued as well.
I have spoken to at least ** different agents and also a few team leaders at MMT but have met with the same pathetic response with no resolution still.