I can't pay you!

I have been trying to pay Vodacom for 2 days now. I have driven to the Vodashop and to Cellucity. They both confirm that my line is active (my phone works, I have no problems with my line) but whenever they try to process payment they get an error message when trying to go into my account. They gave me my account number. I called the call centre who confirmed my account number and sent me details on how to load Vodacom as a recipient to make payments with my bank. FNB error message says my account number is not a valid Vodacom account number. What now??? How do I pay you Vodacom? If I do not pay you, you cut my service, but it is an error in your system that will not allow me to pay. Please advise.