Tata Docomo — sim card

I was using tata docomo sim card number [protected]. I am from gujarat. But my num was deactivated because of some reasons and than after tata docomo shut downs their telecom and merged with bharti airtel. But now that number was registered with one of my bank and without otp i cant manage my account.. So i want to reactivate this number so i went to airtel store. But they told me when the merger happened those numbers which was active at that time is the only numbers we have but mine was deactivate at that time so they don’t have this and cant reactivate. Now docomo is closed and airtel denied so what should i do.?