Make My Trip - Full Refund not credited back to my Account

I have booked * tickets for a Vistara flight from Trivandrum to Delhi which is scheduled to be on **.**.****.While booking I opted for Vistara Flexi Fare scheme under which no cancellation charges will be levied. But after cancellation,Make My Trip gave me a whatsapp message that an amount of Rs.***** will be credited back to my account after deducting MMT charge of ***Rs and ***Rs. That is a total of ***Rs. But I only got ****Rs. When asked about this they blamed Vistara for not refunding the amount. Then I contacted Vistara directly and they assured me that they haven't levied a single rupee as cancellation charge and told my whole refund amount has been released to MMT. But till now,MMT has not given me my refund amount fully. Whenever I call them they are blabbering or blaming Vistara etc.
When I asked them that I wanted to escalate my problem to their senior executives they are not doing that also. I need a solution for this. I am totally fed up with this Portal. I have wasted hours to reach them and explain the issues to each executive. Till date they haven't given me a positive reply.