MTN lose 20 year contract customer over bad service

I was contacted by a sales person from MTN who offered me an additional data contract. The deal seemed to suit my needs, so I accepted the additional contract., this was on the 16th of July. I then received the data sim on the 22nd of July. I think self rica'd and expected the sim to be active within 24 hours or so. two days later the sim was still not active. I then began calling MTN. I then was told to wait 24 more hours, which I did, then called again. I was then told to wait another 24 hours. I have since been told many differtent things, been to 3 different MTN stores. None have been able to assist. the stores tell me to call 135, and 135 tells me to go into the store. The amount of energy this has wasted is not worth any amount of money, I would actually prefer to just completely close all of my MTN contracts, including the one I have had for over 20 years