CANCELLATION REQUEST REVERSED BY CELL C WITHOUT NOTIFYING THE CUSTOMER AND WITH NO JUSTIFIABLE READON! SHOCKING SERVICE!

My data contract expired and when I tried to cancel I was advised that I couldn't as my account was in arrears even though I had an arrangement in place. I paid the account in full on 30 July 2024 and phoned in to cancel the contract. I was advised that I had to give 30 days' notice, so my last and final payment would be due end August 2024 and the contract would be cancelled. I paid on 23 August 2024 and that was meant to be the end of it. Until I received an email reflecting that I owed Cell C. I called them on 7 October 2024 and was informed that my cancellation was reversed on 2nd or 3rd August 2024 as my payment wasn't yet reflecting on their system. Nobody called me to tell me they were canceling my request because I would have provided proof of payment! The lady I spoke to was unhelpful and couldn't help me so I insisted on speaking to a Manager. She promised that a manager would return my call, but I am still waiting, after 12 days!! Instead, three people have called me in the past 3 days wanting me to pay the "arrears". This is shocking, I paid my dues, I gave notice, I cancelled the contract. I do not owe Cell C anything! I am prepared to take this further unless that contract is cancelled and the amounts billed after cancellation reversed. I cannot and will not pay for something I have cancelled. Is this a way to ****** money from unsuspecting people, who followed correct procedure?