Airtel — Not able to port my number from airtel as its not allowing me to generate UPC code

Address:

Navi Mumbai

From Past one month I am trying to port my number. I have been visiting Airtel Store every week and connected with customer care many times. I have been unable to generate UPC code.
Initially they told me as your number is part of family plan, first you have to remove it from family plan. I did that and now my number has single plan. Still i am getting this message once I try to generate UPC code for port.
"upc cannot be generated as there are subsisting contractual obligations with your service provider"