Continuous wrong debit of my cancelled contract

On the 12th July 2018 I told Cell C about the wrong package that I was given by their employedle. Who gave me a wrong network coverage package at my area without even advising or checking if it will be useable. The cancellation department told me that the contract will be inactive as on the 12th August 2018 as it must be given 30days notice. As I speak to you today is 15th August 2018 the contract still existing. They again debited me R309.10 on the 31 July 2018 which I disputed it, but they refused to give it back to me. I then reversed my money through my bank, after that they redebited it on the 15th August 2018. They redebited amount of R309.10. When I ask why they do it, They say my contract still exist. But I did cancel and dispute my wrong network coverage contract. And all the consultants I consultant they were so rude and inhuman towards me. I am so disappointed with your company for continuing debiting my money on a package that they know they were wrong in the first place.