Blame-shifters - NO SERVICE

How can I be liable for paying my account in full, when Vodacom sends me an e-mail, advising that they put my contract on top-up until my arrears is up to date. Then when I phone them to do so, they tell me they can't help me, I must wait for the system to do it automatically (they told me then I should stop paying until the system do it automatically). Then nothing happens, I phone again and ask, then they say they will do it. Then they do it with two of my lines, but the main line stays connected to the contract. I phone again and they advise again that they will do it immediately. NOTHING HAPPENS! Then I don't hear a single word from them for MORE THAN A YEAR. Then when I try to sort it out AGAIN FROM MY SIDE, everything is my fault and I am liable for the whole account???? But Vodacom did not do what they advertised and what they confirmed to do. How on earth is the fault just on my side???