Very disappointed with MTN Customer Service!!!

I am disgusted with the appalling customer service offered by MTN. I have been an MTN loyal client for over 20 years and for the last 4 months they are charging me for a service that they decided to stop offering and didn't even have the decency to inform me of it. I have been to the MTN shop close to home every Saturday for a solid month and a half and they have tried to assist me by placing queries and complaints on my behalf every time I was there, but nobody from MTN gets back to any of us! I think it is time to move on and try to find a better service provider!