Air India — air india not refunding money for cancelled flight due to covid 19 lockdown

I have two tickets booked for round trip from ccu-del (23 april-11 may). The flight numbers are ai - 23 and ai-22. The flights are cancelled due to lockdown. I’m asking for a refund and not getting it. I’m told the amount would be held by air india as a coupon for future use and to be used by 30 sep, 2020. But my trip plan is anyway cancelled and don’t need to travel in the near future. Why am i not getting refund? The lockdown is not a issue created by me or i’m not cancelling ticket, it’s anyway cancelled for the situation! I need my refund and air india is taking advantage of this current situation and harassing the customers by holding the amount with them. If the flights are cancelled due to current country situation, it’s not the customer’s fault. Then why are customers suffering like this. I need my refund by the original payment method asap!!