Air India — Ticket Refund Amount

I had to cancel my Air India ticket no:[protected] and
EXCHANGE TICKET:[protected] due to Covid.
Travel from Sydney to Bangalore on Jan 7th 2021. I cancelled the ticket in Dec.
Since then I have been calling Air India Call Centre support for a refund. They are not helping me and neither processing my refund. I have paid close to 6 Lakh Indian Rupees and waiting for Air India to refund. I have called them multiple times every week. Submitted feedback, yet no one are helping.
I want to raise a legal case against Air India for not paying me since 3 months and torturing me mentally

Below are the Air India case Numbers provided by support
14390368
14259794
Air India Feedback Number: WB-ISYD[protected]

I would raise a legal case for harassment. Please suggest and help