Consumer Redressal

I booked INDIGO Flight PNR no IN4RYN on 14-Feb for Travel Date on 5th April 2020 for 6 Passengers to attend a Marriage in Chennai. I have cancelled the Ticket on 29th March due to Flight Cancellations because of COVID and got confirmation email from Indigo for Full Refund without Cancellation Charges. Now, they refused to give refund and gave Credit Sheel for 6 Passengers, where i know that I will not be able to use this in the next one year. They are citing DGCA Circular no. AV-29011/27/2020-DT stating that Tickets should have been booked between 25th Martch to 14th April, where in I booked the ticket on 14th Feb for my 5th April Travel. First why did they sent me 100% Refund invoice, later they changed their mind and moved the full amount to Credit Shell. The purpose of travel is Over now and there is no necessity for 6 of my family members to travel. I need full refund.