MTN NOT TRANSPARENT WITH THEIR CLIENTS

Good day I have an issue with Mtn, on the 6th I received a call from one of their consultants thanking me for being a loyal customer. The guy was not honest with me as what he did was an upgrade.I was alerted by an sms saying my credit check was successful. The next day in the morning I made a call to cancel the upgrade, the lady said her system is giving her problems she will send a cancelation request. On the very same day I called and I spoke to the another lady around 1 and we spoke for almost an hour regarding the cancelation .She then said it will take 7 to 14 days for cancelation. To my surprise when I went on the app my bill was R2200 ...from R698.I want to cancel all this and not upgrade and cancel my lines