Unauthorised debit order!!!!

<p>So, I woke up with a notification from my bank that Cell C took +-R3800 from my bank account! I contacted them and asked for what is was and was told that it was for the cancellation of my contract. BUT I have already cancelled my contract on the 19th of September and I paid the outstanding balance of +-R4050 directly to Cell C (I had a top up R260 pm contract). The lady then told me that see could see that I made the payment for the cancellation but they didn't allocate it! But it does reflect on the system! Now how on earth can earth can one deduct R3800 from someone's account before checking if the payment wasn't made! Because it has been more than a month since I made the payment and the payment was reflecting on their system for the last month! This deduction from my account caused my insurance debit order to bounce (I am a student and working). So now it looks bad on my name!! I was told that the refund from Cell C will only reflect in 7days!! THIS IS UNACCEPTABLE!!!!! </p>