GoAir — udf refund

Go air is not providing the udf refund for arriving at delhi. I have booked the flight from kolkata to delhi on[protected] and the date of travel is[protected]Pnr-p84s4t)
I have already talked to airlines they are saying they have not charged the udf but how is it possible as the government exempted the udf arrival tax from 7th july.
This is the worst service. Go air is not even responding to the mails.
Other airlines are way better than the go air. They don't believe in customer satisfaction.