Horrible Service from Solomon at MTN

I called MTN to upgrade my contract. I was under the impression that I am getting an upgrade and not an “add sim” as they call it. I complained after I received my invoice that said I need to pay R2045 for my contract. I called 135 on Friday and I was told that an upgrade was not done instead an ‘Add sim” was done. I sent a complaint on Saturday and a gentleman named Solomon called me. He told me he will listen to the call and get back to me. Today he called me to tell me that I agreed to the add sim. I specifically asked if I can use a different number for the upgrade and the guy who helped me said yes. Today I am told by Solomon that the add sim was explained to me. If it was explained I would not have agreed. He then says that an add sim is that simple as though I was supposed to understand. I asked for a solution and he said I should have called 7 days after receiving the laptop. But call how with no invoice? I was under the impression that I was going to pay R1700 plus minus. Solomon then continues to say I should call and request early termination. How is that a solution if it requires me to still pay more. I called retentions to check how much it would be for early termination and I was told I need to pay R9938.50. My annoyance comes from the fact that it is simple that I should have known what an add sim is then it is also my fault that I did not check the MTN app after 7 days to see what my invoice amount was. But the strange thing is I checked and I paid just under R1700 so him assuming that I never went into the app really annoys me. Please assist me with a solution. I do not want to keep this contact and I do not want to pay termination fees as it is not my fault. I really hope that TCF will be app**** here. I have been an MTN customer for so long and this is honestly the first time I am experiencing such service and to be quite honest I am really unhappy at this point.