Discovery of the nasty realities of Banking on Discovery

For more than 24 months I have settled the outstanding balance on my credit card well in time, on average 14 days early. On 25th June 2022 I have paid the outstanding balance which was only due on 12th July. I made one mistake: I paid short by 99c. Clearly a human error. The interest charged is absolutely mind-boggling and totally irrational: R130 for June, R137 for July and R113 for August. Thus R380 interest in response to a late payment of 99c. I have approached the call centre and requested for a reasonable and rational response. More than one request to reverse the transactions were unsuccessful. My conclusion: The Bank do it because they can. Client relations and track record is not part of the Bank’s value system.