Indigo Airlines — Harassment given by ground staff at IGI Delhi airport

Ground staff stops and not allow boarding flight and taken me to a corner people look at me as a suspect. Reason return ticket was after visa validity date.
They simply don't know that a person can board a flight on the last date of visa expiry and upon landing in the destination country one can get 90 to 180 days stay as per visa issued.
Their customer care also so illetrate that harrassing more to change return journey ticket while passengers are in the queue of boarding flight.
Even they click pictures on their personal cell phone of my vis astamp which is a very personal information.
Helpless feeling at that time, lot of harrassment 2 times by Indigo.
We were just promoting our domestic carrier.
Earlier we travelled through Swiss and Lufthansa, it was a delight.
Next time will not board IndiGo and even I am warning others for the same issue.
Pathetic experience.