Vodacom upgraded my 2 contracts without my consent

I cancelled a contract in November 2023. I was paying a fixed amount R2700 for the past 2 years. In December I paid R2200 but in January 2024 I received an invoice saying I should pay R3500. On the 5/6 January 2024 I called Vodacom to enquire about the R3500, they said one of my accounts is an open line and it was over used. I told them to put a limit lock on it. R3500 was deducted end January. On the 8 February 2024, I received an invoice saying I should pay R4500 at the end of February 2024. I called customer care the same day (08/02/2024), the agent told me that some of my contract have been switched from top up to open line, which he said he will fix. Also said that I should ask them to put a soft lock on one of my numbers, and the Vodacom legal department will call me to reduce the R4500. On the morning of 09 February 2024, I received and email saying I have upgraded 2 of my contract, which I never did. The agent upgraded 2 of my contracts without my consent. I called the same day (09/02/2024) I was taken from pillar to post, no one wanted to help me. I want that upgrade reversed and will not pay R4500 after paying R2700 for almost 3 years, it seems like Vodacom is punishing me for cancelling my contract.