Indigo Airlines — Flight preponed by 20 minutes

I had booked flight tickets for Mumbai to Chandigarh via Indigo Airlines on 21st December 2017, for travel date 26th January, 2017. On 26th and 29th of December I received SMS and an IVR call stating my flight timing has been changed from 9:50 AM to 9:30 AM IST on the same date. I received no reminders for this on days before the flight. How do they expect travellers to remember an SMS information received almost a month ago? Should they not have sent another reminder SMS a day before the travel date?

I had issues with the Ola cab I hired and hence I reached the Airport only by 09:05 and requested them for a Boarding Pass as I didnt have any check in luggage and could have made it on time. But they refused stating that the Boarding has been closed. I further requested them to try and make an exception and that we can still make it thorough in 5 minutes (the gate was hardly 3 mins walk) to which the guy over the counter informed me that there is heavy rush at the security gates it being Republic Day, and he has just escorted a traveller to the gates which took him more than 10 minutes.

I was told there is only one ticket left for the next flight (11:30AM) to Chandigarh, which would cost me Rs. 12, 500 post adjustment of the earlier ticket, and that he will put the seat on hold for me for 5 minutes within which I need to confirm if I want to buy the same or not. I took a couple of minutes and decided to buy the same. On reaching the security gates, I found it almost deserted at 9:10, had just 2 people in the queue in front of me, so it seems it was a lie to make me rush into buying the ticket. Also, when I boarded the flight I saw atleast 4 seats empty just around me when we took off, hence the claim that only one seat was remaining also seemed to be their tactic to make me rush into buying the said ticket.

1. The airlines should have sent out a Reminder SMS a day prior to the travel date in case of preponing the flight.
2. The airlines staff refused to hand me my Boarding Pass at 9:05, stating the doors are closed, wherein they could have escorted me to the gates as an exception.
3. The guy over the counter gave incorrect information about the security check being crowded and the next flight having just 1 seat available.