Worst customer service experience EVER!

I called in to CellC in May to cancel my contract. I was assured that my debit in MAY would be the last debit. I received a statement in June saying that an amount of R800 would be debited in June, bear in mind that my monthly premium is R300. After calling an infinite number of times i finally got hold of a lady in the complaints department who assisted with getting someone to help. I was then told that the person i spoke to doesn't work for CellC but one of their hired companies that does their customer services for them and my request was not processed. To the amount in question then being debited, i was told that because THEY MADE A MISTAKE IN LOADING THE DATA ON MY SIMCARD, I HAVE TO PAY FOR IT. How does that even work? I should pay for their mistake? They would however give me a discount and i would pay only R500. I check my statement and the ******* have debited a full R800 from me in June. I still get an email now in July saying a further debit of R100 will go off in JULY!!!! I HAVE CANCELLED THIS IN MAY!!! It is such a nightmare to get any assistance on this, money is going off my account that was not agreed upon. Is this not *****? How are they getting away with this? Retentions seems to never be at work because nobody answers and when they do, nobody knows anything. Even when they have "resolved" an issue, we as consumers must pay for their mistake and they still debit incorrectly!! I am at my wits end. When will i get my money back? if ever... When will this stop? When i ask for recording of the calls i have made, i am told they are unable to provide them. WORST EXPERIENCE EVER! I would have gladly taken up a new cellphone contract with them, but after the hassle of cancelling my mobile router and ALL the unnecessary cost that is being associated with this, i will never deal with them ever again!