Tata Docomo — Non usage of card leading to deactivation of my number

I had ported my Docomo number to a different network long time back, but non usage/inefficient balance in the card it got deactivated. Now I was told to visit Airtel Outlet and I did, But they told me there was no way I can re-activate it again. I have a lot of my accounts linked to this contact, I really want a way to reactivate my number.