Indigo Airline - Booking amount not refunded

I had booked a flight ticket from indigo airlines on ** Feb ** at **** for the date of * Apr **. But due to nation vide lock down my ticket got cancelled. The indigo informed me about the cancellation and when i asked for the refund they didn't reply. And after many days the told that your ticket has been put in the credit shell. I again mailed them that now i can't travel this calender year till Apr** so the credit shell is of no use for me so kindly refund my amount. But they are not giving me genuine reply, instead tey are mailing me how to use credit shell & all nonsense thing. I am feed up of this. I think indigo will gulp my money. Plzz help