FNB will not raise my credit card limit despite my substantial investments with FNB and my impeccable financial track record

I feel terrible to rate FNB this way because they have been an excellent bank through out my career as a medical doctor. But when I was forced to turn to Hello Peter and asked yet again why the credit limit on my credit card was not being raised up from R 18 000 to at least R 80 000, they broke their promise and did not explain. Perhaps they can't explain the faux pas? I can only assume that FNB has some very *********** new staff? Please help FNB to explain why they have limited my credit card limit which is seriously impeding my life as I travel overseas regularly. How does one retain a bank that does not communicate with its customers? As explained previously, despite my substantial investments with FNB and my impeccable financial track record, FNB is making it impossible to bank with them.