Vistara — Flight cancellation and worst customer service

I was supposed to travel on 18th July 2021 from Sharjah to Guwahati with PNR- J79P69, which got cancel due to covid restrictions as per CUSTOMER service. But now they are not even refunding my money instead they are giving me some ### option of having a open ticket till December. If a person is booking a flight for 18th July 2021, that means he need to fly on the same date and not to have a ### option of open ticket.
I had high hopes since it belongs to tata group but my first experience made sure that this is the worst option ever to fly.