Indigo Airlines — cancellation charges

Address: New Delhi, Delhi, 110092

Website: cheapticket.in , indigo.in

I had booked a indigo air round trip 8 tickets from delhi to ranchi on 13th october 2017 from cheapticket.in (Booking id: 1289904 air line pnr : b7vhwi) amounting rs. 20416.
We were going to attend marriage of my cousin brother but due to death of a family member we cancelled the tickets from the website cheapticket.in. On 20th october 2017.
At the time of cancellation they didn't showed the cancellation charges and it was not mentioned on their website also.
They had taken rs.19972 as cancellation charges which is very high.
They are neither waiving off the charges neither allowing me to travel on the tickets.
This is really unfair on airlines part. They should atleast consider genuine and unavoidable reasons. If you cant waive off my amount atleast allow me to travel on my tickets because now we can travel on the dates decided.