Air India — Amount not refunded by air india of cancelled ticket

I have booked a ticket from Agartala to Delhi for 6th of June 2021 and PNR Number allotted Y6KMB but flight has been cancelled Air India and rebooked on 7th June 2021without giving any information about rebooking of ticket.. I can't travel on 7th June
Passenger Detail:-
1. Anuj Kumar Sharma Ticket No[protected]

2. Parul Sharma Ticket No[protected]

3. Prachi Sharma Ticket No[protected]

4. Priyanshu Sharma Ticket No[protected]

5. Tisha Sharma Ticket No[protected]

In this regard I call Air India on 03 June 2021 and also sent a mail to [protected]@airindia.in for cancellation of ticket and refund amount to the bank. As confirmed by Air India Customer Executive that within 21 days amount will be refunded but still no process or info share with me by Air India. I again call Customer care Mr Rashid on 25 June 2021 and he assured me for refund of amount within 5 days. No refund still done by air India.

Anuj Kumar Sharma
Mobile No [protected]
Email Id- [protected]@gmail.com