Indigo airlines - Refund our money

We are expatriate workers. We were buying * plane tickets from Indigo airline on **/*/**** from Chennai to Kolkata then guwahati ticket from Kolkata PNR number CJ*EJJ. But due to lockdown all over the country, our ticket has been canceled by the airline. As a result, we could not travel. Later, the airline told us with a credit shell that we can book tickets from the airline within a year through this credit shell in exchange for not being able to return our ticket money. We have been crying out for double food for the expatriate workers lockdown. Now we need money very much. So we will request you to help us by turning over the ticket money. So we make a humble request.