Cell C - Worst Customer treatment & services!

I have never come across a company of this size that has the worst customer service ever. I am owed a refund of R4000 for the past 3 months and have been given the run around. They will not pay me back my money which Cell C has over charged me for the past 20 months @ R200 per month. After providing them with my bank statements since March 2023 (which cost me money) , they conclude that they owe me less than the R4000. Their calculations were on an over charge of R149 where as I was clearly over charged by R200. I cannot even get a hold of anyone at Cell C that I can explain this too!!! When I called them up today for the 20th time in the past few months, they tell me now that my credit is R2700. So it's clear that they are drawing this issue out so that they do not refund the money they took out of my account without my permission but rather keep it and deduct my monthly bill (WHICH WAS NOT AGREED UPON IN ANY CONTRACT!) When you call customer services, all they can say IS, your case is still open and cannot give me answers as they say it is a finance department issue, and they do not have any contact with their finance department. I have asked to speak to managers as well, they tell me that their managers are on other calls and will get back to me, I am still waiting months later for a manager to call me back. I have even been to their store in Greenstone to try and assist me and not even the manager there was able too. This has been the most frustrating and disappointing experience with a service provider and more so I have been a customer who has paid my bill every month on time for the past 20 years. Please do not sign up with this country's worst cellular network. They may be cheaper but obviously cheaper means compromised service. Pay more and get better customer treatment and services elsewhere!!! I am at my wits end with these people!