Credit Card Additional Charges

I am so disappointed in African Bank. Firstly, I have never skipped any payment. I made a payment of R4000 on the 17th of October 2022. To my surprise I could not see my credit card on the App, on the 20th of October, I receive an SMS stating that the card has been blocked. Why?? I visited the branch and I was told the minus amount is for the Interest-Free Benefit that I was deposited and I did not qualify for. How?? Today, the 24th of October the minus amount is R4.259?? I am not impressed at all. Someone rectify this ASAP. The amount I paid was rejected somehow and still the card is blocked.