Air India Make My Trip - Air India is not Refunding my money for cancelled flight by there side

I have booked my ticket for air India on **nd September **** and my flight was cancelled by the airline so after talking to the Air India customer support I shifted my travel date and booked a ticket for **rd September ****. The problem over here is that I have booked the ticket for **nd September via MakeMyTrip (MMT) but the flight was cancelled from airline's end and then I booked the flight for next day via Air India directly so MMT does not have the knowledge about ACM and after the flight was cancelled I asked for a refund the very next day but the process was very slow so I kept trying for the refund at the earliest now my agent which is MMT here need to get the ACM number so that they can proceed with the RA, but Air India is not sending the ACM number for the **rd September flight ticket.