The worst contract ever gets even worse

My "current" subscription amount is R570 per month. On average, I probably send 15 texts a month and make maybe 3 short phone calls. I don't use social media, WhatsApp or surf the internet. The few times I tried to send a photo, I was told that I don't have enough data. So, to be honest, I am on the worst contract under the sun. But it gets worse... In August, my subscription amount went up to R990. I contacted you guys (5th September) and was told that when I renewed my contract, 1 year ago, I received a very special promotion deal. The promotion was now over and my subscription fee is now R990 per month. I asked them to remove the extra specialness from my contract and refund me. I was told that they logged the call. That I would receive a text within 24 hours, and that I then had to call back to find out what was done. (I have to phone back? Unacceptable!) The next day I received a text saying issue resolved. When I phoned them, I was told that the issue wasn't resolved, it's still open. I would receive a text within 72 hours and that I then had to phone back again. (Unacceptable!). It's now been more than a week and I still don't know what is going on with my contract (or refund). I've been with MTN for almost 20 years. I used to believe MTN was the only real option out there, but for the last 7+ years, I've been nothing but unhappy with you guys. I promise you, I am going to think long & hard before renewing my contract. The only reason I haven't moved to a different service provider yet, is because I suspect they are just as bad. Episodes like these makes me wonder whether I shouldn't give them a try anyway.