Vodacom is overcharging customers and failing to resolve the issue objectively

I discovered in late February 2022 that Vodacom incorrectly charged me for a data line which I took with them in 2020. Trying to resolve the matter with their Consultants has been a nightmare to date my query has not been resolved and they continue to charge me incorrectly and no refund. Can someone with authority please take on my case and resolve my issue please. One Consultant promised to rectify the error and give me a 3 months discount on the corrected amount but seemingly this was never effected on the system. I do hope when the say they record calls they are not bluffing cause I want a full investigation on this matter.