Indigo Airlines — refund of cancelled flight

I had booked my flight for 29th of april 2020 from indigo airlines, pnr llzyqt in the name of vikas chordiya +5 other but due to extension of lockdown till 3rd may flight was cancelled and as per dgca guidelines the airline company will have to refund the whole amount of booking of the ticket booked during lockdown without charging cancellation fee. I made a formal request to the co for getting the refund of the cancelled flight but they have reverted back with the same remarks that shell credit will be created which can be used within 1 year for the same passenger.
I requested to you, kindly direct the concerned airline to full refund the amount in bank account