Appalling service rendered

MTN sold me a contract phone in 2017 mid year over the phone which I accepted. I started paying them through debit order, I was paying the amount of R194-00 for 2 yrs. I paid since then until 2019. After I have realized that it's been long I went to MTN shop beginning of December 2019 at Mall of Africa to ask about this matter. The lady who was serving me told me that the contract ended on October 2019 but hasn't stopped debiting my account since It had already debited for the months but end of November and this continued December the deductions still continued. I have been reversing these transactions from my back incurring the reversal costs but this is too much now as January and February 2020 was still debited. I went to my bank and asked for help, indeed they help me reversing the money from December January February. This repeated again on the end of February. This is unacceptable service rendered by MTN, I don't understand why they keep taking my money because I didn't opt for any renewals or upgrades. I want this sorted out and all monies that are incorrectly deducted to be returned into my account, further more I want my details to be wiped off from their system so that I don't experience this nonsense again.