Discovery Credit Card - Exhorbitant Interest charged for paying 6 hours late

Missed my credit card payment in November by +- 6 hours i.e. I settled the full payment amount 6 hours late. Only happened once before in the past 15 years. R466.71interest was levied on 15 November 2021 and another R355.42 on 15 December 2021. I accept that some penalty would be applicable but is it reasonable to be hit with a R822.13 penalty for paying in full 6 hours late ? Look at the big picture here, the history of your customer and the considerable business he has with you. This can't be right ! Latest correspondence after 1 week remains unanswered.