Terrible customer service and dishonesty

You guys have a terrible customer service and your consultants are liers I'm fed up with service I received from Alberton city Mtn from Nomsa Hadebe.i asked her the special that you had for 20Gb anytime/during the day and 20Gb at night Sim deal that you had that was R199 for 24 months also had a router that was on special for R30 for 24 months, so Im now shocked to receive statements from mtn billing me more than R300 a month. The first month I understood why I got billed R369 because she said I got the contract on the 19/03/2020 so they are going to charge me for the extra days. Now it's month 2 I see they are going to bill me R329? For what? Because according to my understanding I'm supposed to be billed R230. Firstly the router didn't work for a week because she failed to active it then I asked her to cancel it she refused and her other colleague a gentleman helped and actived the router so the extra days that I was charged for in the month of March I didn't even use the router. Then I asked her to change my password she said she doesn't know how to personalize my password now im being over charged /over billed. I want to cancel this contract with immediate. You guys failed.