Indigo Airlines — time spoil and forced to take next flight with extra amount charged and adjust previous amount

Dear team,
I booked flight from indigo 6e 755, from delhi to mumbai 4 pm, boarding time is 3:35 pm 25 minute before the flight time.. However i reached 40 minute before check in that is 3:25. It means i reached 35 minutes before boarding time and 10 minutes before gate closer. And there were no rush on counter so i can easily took my flight, however inversely they are spoiling the time in argument that time is to close the gate 25 minute prior and closing the gate 30 minutes ago and forcing to buy tickets for next flight

I reached airport after 3 hours stuck in traffic and indigo didn't allow me for 3 or 4 minute late and also waste my time and console to take next flight ticket to book there vacant seat they charged 3200 more rupees.