Vistara — Air travel

Website:

www.airvistara.com

I had booked 4 tickets in February for family vacation in May. Due to the lockdown, flights were cancelled. I dont want a change in date as it looks unlikely that i will be able to take that family vacation to the same destination. Why is the airline not refunding without cancellation charge?
- Not my fault that the airlines didnt fly
- my cancellation is not causing revenue management leakage - as flights havent flown
- Why should I be forced to change of dates - when I am unlikely to do the same vacation
Airlines is quoting DGCA rules that refund is applicable only to people who booked in March - is it my fault that i booked early? Dont see any logic