Unable to port number away from Vodacom

I have been trying to port my prepaid number to FNB Connect since December last year without any success. Whenever FNB Connect attempts to port my number it is rejected as the Vodacom system indicates that I have an outstanding amounts due. I have phoned the Vodacom call center numerous times to check what is outstanding and thus far they have found nothing. I do not know what to do anymore. Not even the Tygervalley Vodashop could help me as my account seems to be on the new C3D system which they to not have access to. Vodacom please help!