Air India — Ticket cancelled but refund not received for 3 months now

I had booked a ticket with number[protected] from Bengaluru to SFO for July 21st which was cancelled by me on May 30th. I have been following up multiple times via email and calls and keep getting informed that the refund is done and the money will be credited in 7 to 21 days. It has been 90 days now and the money is still not credited. Also, they refuse to give the transaction reference number to check with my Bank despite repeatedly asking for the same. There is no escalation contact also for talking to on this issue. I would like my money refunded asap.