Go first - Boarding Denied flight overbooked

We were denied boarding by Go First staff and faced rude behaviour from the ground staff of Go First Airlines. The web checkin portal was allowing only * seat to be booked for * tickets even ** before departure time (proof held) which indicates possible overbooking by the airline. E-mail from airline nodal officer upon complaint indicates that the cut off time is ** minutes before departure. We reached the kiosk of the airline well within this time limit (signed ticket from ground staff held as proof). On top of this we were behaved with rudely by the staff of the airline. Since, we were denied boarding on false grounds and because of the web check in error at the company's end/ possible overbooking of the flight we request compensation in accordance with DGCA rules for such cases (INR **,***)