Air India — Poor service and scamming

I had Booked a ticket on Air India on 27 July 2021 (Confirmation attached) for Delhi to Hyderabad (31 July 2021, 9:55 am).
Due to unforeseen circumstances, I had to reschedule my booking date to 7 Aug 2021.
Intimated by the website to call the customer care for rescheduling (all airlines have this feature in their website itself). (1 Free reschedule is possible 12 hrs before the departure ).
I called customer care well in advance for the same only to be mentally harassed and put on hold. Due to the incompetence and unsatisfactory attitude, I was put on hold for more than 5 hours causing my free reschedule option to become invalid.
In addition to this, there was no way for me to reschedule my flight as I kept getting transferred and hung up by the substandard and poor behaviour of the staff.
This resulted in the cancellation of the ticket to save whatever amount I could.

Mental harassment and torture for a day in addition to monetary loss of 10000 due to incompetence by airline staff.
I still have not received my cancellation refund (more than 24 hrs have passed).

Have also put up multiple emails but no response by Air India staff.

*All tickets and cancellation documents are attached with call screenshots (can not upload call recordings as file format not supported).