Credit card paid but still no payment indicated for December 2018.

I always pay my credit card on the 24th as I receive my monthly salary around that time, the minimum payment has been around R1000 for a while now. 24 October 2018 I paid R3000, 24 November 2018 I paid R3000, I then received my salary early so I paid R5000 on the 14th of December 2018. Now yesterday I received an unpleasant call from one of the standard bank consultants telling me that I have defaulted on my payments, I don't know how is that possible, because I am given until the 11th of every month to pay my credit card and I have been consistent with doing so, my credit has been impacted negatively as a result and I am not happy about the situation. I don't appreciate receiving a call given to people who don't pay while I have paid.