Makemytrip - Promised refund never came after numerous followups

I booked a ticket using the MakeMyTrip mobile app. At a later point, I called them to request for rescheduling the trip, to which they said I have to directly call the airline to reschedule. I called up the airline (Air India) and successfully processed the rescheduling. Then when the time was due to do the web check-in for the ticket on the airline's website, it showed an error message that the ticket PNR is invalid. Then the horror started unfolding - I had to be on call with the MakeMyTrip customer service representatives and Air India customer service representatives (both sides blaming each other) for close to ** hours on that day to figure out what happened, as the flight was scheduled to depart the very next day. It turned out that the cancellation for the ticket was initiated by the MakeMyTrip software automatically or by one of their agents. It took so many hours of calls to convince a MakeMyTrip supervisor of this reality and finally agreeing to resolve the issue from his side. Then he requested me to pay for the reissuing of the ticket and promised that MakeMyTrip would refund that amount. He sent me an email as well for confirmation. He said that the refund would be processed within ** hours. As of today, it is more than ** days but no signs of any refund from their side. I call them almost everyday and they say that an agent is still working on the ticket and they don't know when the refund will be processed. I have gone through so much mental pain and tension talking to MakeMyTrip with no resolution in sight.