Account miscalculations which Dion Wired has admitted to but has since not even fixed!

I called Dionwired on the 14th May 2018 to query my monthly account installment as it seemed to have been miscalculated. i was attended by Veon October who confirmed that indeed the reflected amount was wrong. He couldn't re-adjust this and that's when i asked to be put through to his supervisor, Brogan Groenewalt who couldn't assist either. I persisted to rather speak to both their superior Daillon van Wyk. He blamed the miscalculation on a system error and promised to get back to me with a right figure, to date he hasn't done so. I called again on the 16th May and asked for feedback and got none. This morning i called as i need to pay my account and spoke to Mbali who then kept me waiting while she gets her supervisor to attend to me. I kept holding for such a long time until i ran out of airtime. No one has since not even returned my call. Dion Wired'service is totally unacceptable, overcharging their customers, not even attempting to apologize or at least rectify their mishap. i can't wait to settle this account and close it off completely. I have no intentions of ever wanting to be subjected to this kind of treatment by a company. A company which i have always paid on time and not even on arrears. i can confidently vouch that my account with them is in good standing. the company isn't owning up to their mistake nor making any changes to ensure that their customers are happy with the service rendered to them.