Make My Trip - MMT Assurance not Refunded after cancellation

I have booked a round-trip ticket from bangalore to lucknow on **th dec **** (Booking id: NF**************], * persons, travel dates feb ** (Onward) and march * (Return) under mmt assurance which gives zero cancellation charges at additional cost.

Due to change in plans, i have cancelled tickets for * persons out of * (Full cancellation, both onward and return) on **th feb. When i was cancelling, i was presented inr **** on mmt website as refund amount that i will get. After i proceeded with cancellation, the refund got delayed by few hours. When i checked later, i received only inr **** as the refund amount (Booking id: NF**************).

When i contacted the customer care on ** feb on the discrepancy, the agent mentioned that the zero cancellation is given only if all passengers have cancelled the ticket. However this is not what is presented on the website of mmt, and also the mmt did show zero cancellation (Refund inr ****) when i tried cancelling for partial set of passengers. The agent share t&c regarding zero cancellation charges, but even that shows that i am eligible for inr ****.