Air India — Delay in Refund

I had made a booking with Air India for flight AI302 from Delhi to Sydney with eticket no.[protected] for 26th March. I made a booking on 24th March, 2022 and cancelled the ticket next day since I was informed that Singapore will be operational from 27th march from mumbai to singapore to sydney and since Singapore airlines was more convenient for me, I cancelled Air India ticket on the call after detailed chat on cancellation fee and time of refund which was told will be 21 days.
It is been more than 21 days and there is no concrete response yet on by when refund will be processed. Multiple calls and emails have been exchanged with no solution, refund or any commitment on refund timelines.