Vistara Airlines not refunding full amount for cancelled flight

I’m facing extreme resistance for the refund from the airline (Vistara) for the flight scheduled to fly during the Lockdown 4.0(29th May 2020) but booked before Lockdown 1.0 (27th Jan 2020). The airline is fleecing the customers in the absence/unclear guidelines from DGCA and are keeping the money in a credit shell against customer’s approval. Because of this the customers are suffering heavy monetary loss. We had multiple telephonic conversations with the airline (Vistara) and booking portal website (MakeMyTrip) for the same and have been denied the full refund.
Attaching the email conversation with the airline for your reference.
Can you please help me in this dire situation?
Please let me know if you want me to furnish any more information further for the same.
Awaiting a positive response.

Namita Garhwal
Hyderabad 500032,  Telangana
Email: nxxxxxxxxxxl@gmail.com