Air Asia — forced to do web check in

Address:	560001
Website:	www.airasia.com

I have book ticket from ranchi to bangalore for 08/11/2017 in air asia. I received call today from one of the customer service executive regarding web checkin. The executive forced me to do webcheckin but i refused as i did not have any preference. Lately she started threatening me saying we will see what happens in airport.
I am really worried whether we will get proper seating in the flight or i can travel also.
She told me that selecting seat is mandatory, but i do not understand if something is mandatory it should be there in the website or application.

After this incident i dont know whether i will prefer air asia for my future journey and suggest my friends and family also.

Please help me. Hoping for positive response

Note: i have booked my ticket from makemytrip.