Vodafone — Unable to PORT Number

I want generate a UPC code for changing the Mobile service Provider but the current service provider not generating the UPC with the reason "Outstanding Payment". I have paid all the outstanding amount and then tried again for UPC code but still service provider sending same message that you've outstanding amount.

Name: Prashant Phulsang.
Mobile Number: [protected]
Date of Incident: 30th July 2020
Email: phulsang.[protected]@gmail.com