Incorrect Billing - Poor Service

I've been a Vodacom customer for over a decade. And I've never had any problems with Vodacom, but their service has recently become ridiculous and unreliable. After receiving a quotation, I took out a new contract line in November 2022. They invoiced me accordingly in December 2022. In January 2023, I received a statement and a tax invoice for which I was incorrectly billed. When I called the call center, I was told it was an error and that they would issue a credit and correct the problem for future debit orders. Surprisingly, I continue to receive messages and statements with the incorrect amount.