Indigo Airlines — boarding pass refused at counter at delhi airport

Me ( H Roy Chowdhury), My Wife (Gouri Roy Chowdhury) and my Sister-in-law( Smti Uma Bose) were to travel back to kolkata by IndiGo On 13th Nov’17 by Flt No 6E219 at 6.50 AM from Delhi Airport. We were carrying boarding pass as we already checked in at home. I stood in the Q at about 5.50 AM for our registered luggage only and when we reached desk it was about 6.05 AM i.e the reporting time and person issuing boarding pass closed the counter and asked us to approach D1/D2 counter to get boarding pass . There was no announcement for counter closing and priority announcement and no official came forward to assist passengers leaving by next flt, in Q to get boarding pass on priority basis which is generally followed by other airlines. One official suggested to board the plane immediately with hand luggage only and remaining luggages( two pieces only) would be sent by next flt at 7.50 AM and we immediately agreed to this proposal. But no staff came forward to help us to get the flt, although repeated request made by us. We are all senior citizens and we found no help from airline staff. The door of the flt closes 25 minutes before departure as per rule and there is a provision for helping passengers to board the flt with hand luggage only, when time is short. Nothing has been done in this direction.
Moreover, when I approached D1/D2 counterat their advice, they refused to issue boarding pass immediately and kept us waiting upto 6.50 A M saying that fresh tickets required to be issued after departure of 6.50 flt . We had an impression that we would be accommodated to next flt at 7.50 AM or at 9.50 AM with the same ticket . But they issued fresh tickets treating us no SHOW although we were in the Q from 5.50 AM. Finding no other means, I had to purchase fresh tickets with additional Rs 31000+ for flt no 6E 591 at 9.50 AM and we got boarding passes for seat nos 9A, 9B and 9C. My old ticket money was totally forfeited and tax was adjusted with new tickets. Being senior citizens, we feel cheated and perturbed. I have narrated situation elaborately and if you feel our complaint is justified, please advise AirLines to fresh ticket fare and they should say sorry to us.
Thanks and regards