Air India — Unreasonably high charges added for change.

I contacted the Air India reservation office to ask if I can change the dates for two different tickets more than two weeks in advance. Instead of offering the first free change, I was told that a penalty of £150 per person will be changed plus the applicable fare difference charges. I don't understand why I need to pay a penalty and fare difference on the same difference if I am not cancelling the ticket. the total value that they were charging was about one lakh twenty-nine thousand Indian rupees which was almost the price of the main ticket. so I had no choice but to cancel the ticket and pay the total cancelling charges of £600 which is £150 per person without even travelling on the air in India. the air india regulators need to investigate these cancelling and refund policies which is a total scam and rip-off of customers.
date of travel 24 june 2023, 16 july and 24 sept 2023.