Vodacom contract was cancelled but they still debited monies

My contract with vodacom ended in December 2019. I chose not to extend it. After that, Vodacom continued to debit money from my account after I requested it to be cancelled. Over the course of 2020, I called many times and they still did not cancel it and took monies from my account. I called again in December 2020 to cancel it but they only cancelled it in March 2021. I requested reversals for those amounts, i was only able to do the reversals for the last three months. Now vodacom claims i owe them those amounts and is affecting my credit score. I called to request recordings of all the calls I made over 2020 proving that I indeed asked for a cancellation but they said I must go to the courts. This is very unfair as they technically owe me a lot of money that they took even after me asking them to cancel this. Additionally, they took money from my account for Insurance that was not authorized by me, I called and they said I will be refunded but it never happened either.