Continuously debited even after 24 months contract cancellation

I’m still sitting with the same problem since November 2019. I cancelled my WiFi/data contract with Telekom cause the 24 month period was over. I even got an sms from Telekom to confirm that they received the cancellation and confirmed that it’s cancelled. Yet after that Telkom continues to bill and debit me monthly till today. I’m not sure which other channel to use to get this resolved because I called to complain and they assured me I will no longer be billed and debited cause they can see from their side that it’s cancelled. Yet money was again debited in December. I decide to go directly into a Telkom store to query this again. Thy lodged a call me back but I was never called. I sent a message to Telkom, still nothing. This is my 2nd time complaining about Telkom on Hello Peter. This company debited me again in January. I foresee another debit again in February. I just can’t take this anymore. I will never again take out another contract from Telkom. I have never experienced such incompetence from any other service provider before. This company is the worst of the worst.