Cell C cellphone contract overcharged me and threatened to take me to court when I requested the cancelation

Do not open a contract with cell c. It's been 2 years since I opened my contract that was supposed to ending February 2025 which I paid R760 every month in full until March 2025. Every month I'm still being billed for the contract. I went in to the shop they refused to assist me and gave me a toll free contact number told me to call them to cancel the contract. I called the customer service center and the consultant Harabo/Karabo threatened my father to say he will get Cell c to take him to court if he does not pay the 3 months of overcharged fees. Even after my father explained countless times that the Sim card has not been receiving benefits for the past 6 months. Harabo/Karabo then went on to mock my father by completey disregarding everything he explained about the overcharged fees and insisted that he opened up a new contract. These people have no customer service etiquette and no intentions of closing this contract even though I paid it up in full with bank statements as evidence. Can someone from management please get into contact with me about canceling this contract because clearly your cancellation department has no intention of doing so.