Mango giving invalid vouchers

I booked a ticket and unfortunately President declared Lockdown. Mango issued a voucher that I can use at a later stage. To my surprise when I tried to book the same route, now that the economy has opened up Mango is telling me they stopped flying to that route I can give ticket to someone else as they do not refund. My point is :we all have been affected by covid and why should I the cinsumer suffer. As a big company they are not willing to suffer losses, what about me. I didn't want to cancel but wanted to rebook the same route and now they are refusing the refund also. I even asked them to book me on the airline they working with with no success. They have to refund me, they are robbung the customers. Mango, I want my money back and will not stop until I get it. No point of giving vouchers and you stop the route.