Vodacom cannot find my number but Vodacom App can

On the 14th of September I called Vodacom to ask to downgrade my package to a cheaper option. When I received my latest statement the downgrade was never app****. When I called Vodacom they informed my that they converted the number to Pre-paid. When I asked them who gave them that permission, they indicated that they don't know. Funny enough the automated system can find my number and indicate that I am due for an upgrade, and that I still pay my account, but the customer care line says I have a prepaid number. So Vodacom, my question: Why do I still pay for a number that is supposedly prepaid and why can you not find my number on your system but my Vodacom app has no problem? And why didn't you downgrade my account when I asked for it?