Cellc debiting my account 2 months after the contract was cancelled

About 4 months ago, the contract I had with CellC for 24 months was finally paid up, and I didn't need an upgrade, as I am still content with the device I was paying for, then CellC managed to convince me to take another contract for R99, which was just a sim card with 8 GB day and night data. I agreed and they delivered the new sim card, but when they had to debit, they debited R250 instead of R99, I was fed up and went to the CellC store to enquire and then I was told that I had been falsely advised that the debit order amount is R99, when it is actually around R300, I was furious and told them to cancel the whole thing, I spent hours in a CellC store talking to the Head Office and getting the run around, being **** to again AND being offered another "great deal" to remedy the situation. I was adamant that I wanted everything cancelled, and eventually after about 2 hours, they agreed to cancel my contract, and I received an sms to confirm same. They didn't debit my account in July but this morning (22-08-2017) they debited my account for an amount of R200, what the hell for?! I don't have a contract with them, and they don't load data or airtime on my sim anymore. So why do they suddenly debit my account without any explanation. I want that money back, as it has been left in my account for another service provider. CellC are a bunch of ******!!