Spice Jet Airlines — denied check in to a delayed flight

On 6th jan 2020, i was traveling from dibrugarh to mumbai via kolkata through spicejet airlines. While trying to web checkin, all the seats were chargeable. This, as far as i know, is against dgca rules.
And when i reached only 2-3 mins later than the 45 min window for counter checkin, the counter was closed with no operating staff around.

I was denied checkin. This although the flight was delayed by almost an hour. Pls note that this happened in the dibrugarh airport which is one the least busy airport and security to gate takes only 5 mins.

The manager was no where to be found and the staff (Was very rude) and did not even allow me to have a 2-min word with manager. It was none of their concern that i had a connecting spicejet flight from kolkata. I have never seen an airline as this, with utter disregard to its customers.