Unwanted Ipgrade

I received a call from a vodacom agent asking me to upgrade, I already have 2 contracts with vodacom and the 3rd number is prepaid. I told him I am not interested in upgrading, but if he could better my current data plan then I would be willing to consider. He told me about a data plan that was cheaper and offered more data than my current plan, of which I said, if he can give me that plan on my current data contract then I would be very happy, I further stressed that he leave my prepaid number alone and he shouldn't do anything on it. We both agreed and the deal went through, the contract came with a router and a R1000 voucher...I was led to believe that he had upgraded one of my current data plans but the agent instead upgraded my prepaid and turned it into a data sim, I immediately called them, when they changed my prepaid to a data sim, which was on the 1 August, they sent a courier to come and collect the router and the voucher. It's been 2 weeks now I am calling customer service trying to rectify this and all they say is that they will escalate my query and send it to someone in the back office and that they are sorry for the inconvenience. This unwanted upgrade 😪 started on the 1 August 2023, it's 17 August 2023,.almost 3 weeks later and still no assistance. Not only can't I make or receive calls now, but vodacom has also debited on my account. For something I didn't ask for nor do I want. What can one do to stop vodacom from giving us such horandous service?