Refund of Rs 2036 not processed even after 1 month

Location/place: Mumbai

Name of company/service: Kingfisher Airlines

I have reserved a ticket with Kingfisher Airlines which I cancelled since I had to postpone the trip to next day and rescheduling was about Rs400 expensive then rebooking on another flight. So when I cancelled it KF promised me a refund of Rs2036 accordingly I agreed and re booked on a different flight. After one month of cancelling since i did not receive the refund I called up their guest care who said that refund amount was Rs1600 only to which retaliated and asked for the amount promised, but never got any update from KF Airlines for another a weeks time which they promised would call me in 24hrs after checking the call details, so I called up again to my shock the amount was now Rs1400 which the agent was ready to process but I did not agree. Now they claim that they do not have the phone records so they are finding it difficult to process the refund of the committed amount and accepts their mistake.