The worst service I have received within only 3 months after taking the contract

I took the contract in October and arranged for my account to be debited on the 26th, Cell C did not debit my account, I called several asking them to debit the account and I asked them to confirm if they have the right account details they kept on saying they will do it the following day. I ended up going to their store and the only thing they said was that they are sorry and gave me a page with account details and asked me to pay cash, I paid via EFT and this was at the beginning of December, I continued to receive texts saying my account is in arrears, end of December they did not debit again and I paid via EFT still I received text saying they will cut my line and report me to the XDS credit bureau. After receiving the sms saying they are going to report me to the credit bureau I went to the store and even showed the manager the transaction on my banking he confirmed that the details are correct however he wont me able to help me since it was Sunday and people that he need to call only work Mon - Fri. I decided not to go back to the store and called Cell C they said it doesn't show on their side that I have paid and they told me to send proof of payment and still they gave me the run arounds saying they haven't received the proof of payment, finally yesterday (24th Jan) they said they have cleared my account. But this morning (25th Jan) they debited the amount for October to December that I have already paid. When you ask them questions all they know is "I don't know" or "sorry mam", I don't know how many people I have spoken to from Cell C but none of them seems to know anything. Yesterday out of the blue the phone just died. I have no peace after taking the Cell C contract.