Make My Trip - Non issue of eticket

I had booked my mother's return ticket from. Sanfrancisco to Bangalore. Travel date was **/Aug/****. On **/Aug, I requested MMT to change the date to from **/Aug/**** to **/Dec ****. They said it costs *****.which was costly for me. So I told them to check any other day where i don't have to pay anything or just ****-**** as date change charges. Preferably zero charge is what I requested. So the representative said he'll check for tickets in the same segment that I had booked. On **/Aug they confirmed that date change is done with zero charges is available for **/Jan/**** and shared the itinerary with me. They said the e-ticket will be share in ** to ** hours which is still not shared with me till date. I contacted them after ** hrs when I did not get the ticket as promised by them. They told me that they cannot issue the ticket. I called Air India and they confirmed that MakeMyTrip did not complete the process with Airindia after itinerary was issued. Make my trip supervisor also accepted that it was their mistake. But till date ticket is not issued. I had been asking them to refund the money. They kept quiet for *.* months and now when * days is left they are calling and saying they will issue ticket now when the travel plans changed and alternate arrangements are done because MakeMyTrip did not respond for *.* months.