Credit increase not reflecting

I increased my credit card limit online and on the FNB app. however after receiving confirmation that the increase was accepted and accepting the debicheck mandate, there has still been no increase? It normally takes effect immediately, however it has been since the 26/08/2021 till now nothing has changed and when I called the call centre I was told it would reflect in 24 to 48 hours, If the credit increase limit is not accepted why does FNB still send confirmation? doesn't make sense. Can someone please assist with the above. Thank you