Contract cancellation

Can you please help me cancel my vodacom contract? I had my contract in 2020 and it expired this year. I didnt want to upgrade my contract at first. And i wanted to cancel it but it was still debiting from my bank. So i upgraded to data package but i had encountered a problem of overpricing and bills of things i wasnt aware of. And i told them to cancel or block options that will add more bill. However i am not happy with this contract and its making my life difficult as a student. Can you please help me cancel coz its unbearable and im tired of getting surprise bill