Air India Express — Not able to Modify my ticket: PNR No:KLULNN(Date 25 th June to August 20)

Address: Khobar

Sir,
I am Fazalul Rahman living in Saudi Arabia.This is to inform you that I have booked a flight in Air India express (PNR No:KLULNN
Actually my ticket date is 25 th June and I need to modify it to August 20 due to current circumstances.
I have call customer call more than 100 times, visited city offices, and even emails with no issues
If not possible please refund my money.