Poor client service and misleading me

I upgraded my MTN contract on Black Friday 2018 over the phone ( Always a bad idea over the phone ive learned but it was black friday and shops were full). My previous contract from which i upgraded from featured minutes, sms and 50GB data all going to the same sim/number so all was good and well. With this upgrade MTN has misled me. I specifically asked for a similar deal like i had at the time( minutes, sms's and 50GB or bigger data package) and I specifally told them that i want a new number/sim and all my minutes, sms's and data should go to my new number/sim which they sent me along with the phone a while after doing the upgrade over the phone. I can still remember our conversation was that i would for the first month receive all my minutes, sms's and data package on my old number/sim( Because of not having the new number/sim yet) and thereafter i would receive everything on the new number/sim. This was not the case. Every month went by and i only received my data and no minutes and sms's thus paying for something i was not getting fully. I have tried to resolve this issue numerous times over the call centre, at the branches, via email and i even got an MTN employees personal whatsapp number at the store who was not of much help either and therefor causing a heck of alot of inconvenience for me the paying customer in my spare time. And just to put the cherry on the cake i was contacted by someone from MTN a while ago asking me if i want more minutes with my contract for X amount more a month. I told them im not receiving any mintues and sms's and have been trying to resolve this issue for more than a year already and told them if they would sort it out i would like more minutes yes. Still till this day not resolved and MTN has charged me more on my debit order( Even more than the X amount extra for the extra minutes for some reason) and i have thus stopped paying my contract after almost a year and half of struggle with them. Their service is so poor that even after i stopped paying them due to being fed up with this struggle, not one single consultant or person from MTN has phoned me to follow up on payment. Only up until very recently i figured out what was going on which no one in the MTN stores told me. On the day of the upgrade in 2018 the person over the phone created 2 contracts. One where the minutes and sms's went to( Old number/sim) and the other where my data goes to( New number/sim which they sent me along with the phone and which i have been using for almost a year and a half). I pickup this up when i downloaded the MTN App recently and saw another number linked to my account which was receiving the minutes and sms's. I was misled by the person over the phone and was not aware that there were 2 contracts and i have been using the new sim they sent me with the phone ever since and thus only received data and nothing else and thus paying for something which i have not been receiving fully. MTN has already taken my sim off the air which is fine because i stopped paying them due to not getting this issue resolved and they are debiting my account with even more money for something im not getting. Terrible administration and client service and misleading of long time clients on MTN's part. I now wish to cancel everything with them completely and im not willing on paying any penalties or any money i supposedly owe them. I have been wronged and they are quick to try and sell me something over the phone but when it comes to sorting out issues they are nowhere to be found. Still waiting for a reply