Make My Trip Pvt Ltd - Flight cancelled by MakemyTrip

I had booked a connecting flight from Singapore to Pune via Bangalore in Makemytrip. SIN-BLR was air india express flight, BLR-Pune was indigo domestic flight. Due to change of plan, I wanted to change dates of international flight and cancel the domestic flight. When I called Makemytrip, they suggested me to do the modifications directly with the airlines. So I changed the date of airindia express and canceled indigo flight in their respective website. Then to request a refund, I had to fill a form in Make my trip website, I filled and uploaded the Indigo cancellation confirmation. I even called the Makemy trip customer care, he said that only indigo is cancelled and airindia express dates are changed successfully. But after few hours I get a mail that the air india express flight is also canceled !! I repeatedly called customer care and said I did not cancel the ticket and it was the fault of Make my trip guys. But they just raise a query and make some reasons that they are not at fault and they say I have cancelled the air india express fight. But I have never requested them to cancel it, why would I change the date if I had to cancel it? The Customer care of Make my trip do not respond properly now because they know that it is their mistake that the flight got cancelled. Please help to resolve this issue.