Account is paid up and I am still being billed

HI <br> <br> I received a bill from Vodacom and my account has been paid up. The Credit Bureau was updated in July already to paid up. I called vodacom and no one can help me. They cant detect my ID number or the phone number in question but also would not check with my old account number in the bill they sent. The consultants keep putting me through to other consultants who cant help me. They check and try to help, then they say only the accounts department can help me but then i get directed to another person that cant help me. With the last call, i wanted to make sure i am at the accounts department and this consultant ignored me when i asked him and kept telling me he can help just like the others said.. He then through down the phone but never reassured me that i was at the correct department. Please help, this account was paid. I need a paid up letter please. <br> <br> <br> <br>