[Resolved]  Indigo Airlines — inappropriate behaviour by indigo personnel resulting in missing the flight

Hi i recently booked a flight for my sister from Lko to Delhi, and we reached the airport on time, while my sister was waiting patiently in the queue when her chance came the indigo personnel said that the boarding pass will not be given since she was late and now only 44 minutes are remaining for flight to take off and in no way she will be onboarding the flight, not was he only rude but also HE DIDN'T MADE ANY LAST ANNOUNCEMENT FOR onboarding ticket, we requested him so many times like still 45 mins are there for the plane to take off, you should take her in but he didn't listen at all . When i tried to talk to him he just hung up on me, such unprofessional behaviour from INDIGO. Later he sent a guy to my sister saying we will put you on another flight FOR RS 1500 . Is this whats expected from such a big airline . If the flight was overbooked the airlines should take the responsibility instead of charging the customer by such illegal ways. I am attaching the proof that we arrived at the airport around 20 mins before the 45 min deadline as claimed by indigo(screenshot of cab taken) I request to have a look in this case and help me out. Flight details:
IndiGo Flight(s)
Date From (Terminal) Departs Flight Number
(Aircraft type) Check-in/Bag drop closes To (Terminal) Arrives Via
10 Jul 19 Lucknow (T2) 06:15 6E 769
(A320) 05:30 Delhi (T1) 07:25
PNR :AF95GM