VODACOM INCOMPETENCE

I was on a prepaid account and converted my account to post paid. <br> In April 2014 I requested Vodacom to change my account to prepaid again. This conversion was done but I was billed from November to date which I can understand to some extent..... I called the call centre on 05 January when I was burgled as they had \disconnected"my account. I now receive a letter threatening legal action on my prepaid account? I have tried sorting this out since 13 or 14 January and I get told I must dial 082111 (customer service). They then put me through to *** (collections)"