Incorrect billing

I had a Vodacom Fibre contract since March 2019.In Sept 2020 I changed the package on the contract and excepted the quote. The line speed was adjusted to the new package , BUT since October 2020 they have been billed me incorrectly. Ive loddged numerous complaints with their so called customer care centre since October. The last ref no given was SR***.I was given the assurance on several occasions that it has been sorted. With a shock I noticed today, 1 Dec that they still *****LING my money , the billing has not been corrected. I made several calls today demanding to speak to a Manager, just to be told they will contact me . Needless to say I still wait like a fool for a callback. I have spend hundreds of rand on call charges to try and fix Vodacom's INCOMPETANCE. I am beyond mad and extremely frustrated , that they do not value me as a client. In that case, I can take my business somewhere else where I will be valued. Am I asking to much for you to fix a simple problem ? You should be ashamed of yourself as a leading network provider with the way in which you treat your PAYING customers. I neex this fixed immediately. I will also be posting this complaint on National Consumer complaints department.