Frustrated customer

In October 2023, i was charged an amount of R57.50 for a service i never asked for or agreed to. Since October every time i get my statement i call them and sit on the phone for over half an hour explaining the same story over and over, they confirm its been escalated to the accounts department someone will call you, i then send an email confirming the conversation i just had. Low and behold i just received my statement and surprise it's still there. This is so frustrating for such a big company. They load services you know nothing about then its an issue to remove it. I have just had enough and i am not going to call them again because clearly it does not make a difference.