MTN is useless!!!!

I am so upset with the lack of customer service i got from MTN call center. They decided to bill me 3 times in January. It turns out that they decided in October 2019 to activate 'additional usage limit' which i didn't ask for so after insisting that they reverse this thing and refund my money!!! I have called since 29th January for my refund am told that a credit does not reflect they will send me a refund once it reflects, I have spoken to Thulisile Dube, Sonia Kabelo, Qolisile Manya(kept me on hold for 20mins and had the audacity to update on the system that i hung up), Patrick Seakamela said on th 18th Feb that he would call me back , needed to speak to his Supervisor. I am still waiting. It is nauseating that you guys think you can just mess around with my money... I paid the 2 invoices because you kept on cutting my line and thought i would address it with you but i am being disregarded which makes me really mad...If this is not resolved i will take this to the highest authority!!!!!!!!!!!!!!!!