Tata Docomo — not accepting porting request

Hi,
I am using tata docomo postpaid line. Now i wanted to port my number to airtel because of network issues. So i have raised porting request. For the first time the porting raised by airtel to tata docomo was rejected due to billing issues. Immediately the next day i did complete payment. Even i have done one month advance payment. After that i have raised a request atleast 10 times in airtel office. But when i call tata docomo customer care, they always say that they have not received any request. I have fed up with this issue.in airtel office they showed their screen as well to confirm that the request has been raised from their end, but there is no such facility for tata docomo. Please help me to get my number ported.

Thanks