[Resolved]  MakeMyTrip India — did not receive promised cashback

I have booked flight from kolkata to pune for 26 th march. Applied mmtflyhigh code that gave me an instant discout of 300 or around and i was about to receive an additional cashback of 500 within 21 working days as per the t&c of the code. But after 21 working days when i tried to contact mmt customer care via mail for the same concern, they are making excuses like the coupon was valid for site only and all nonsense stuffs. Now after more than 30-35 working days they are replying on a daily basis that they will get back to me within 24 hours. But no action from their end till date. I want my cashback. Never going to book any flight from mmt ever again. What should i do now?