FNB Revolving loan issues

FNB offered me a Pre Approved Revolving Loan which at the time I took because I needed it. In less than a day it was approved and added to my account with a R0 Balance. I have phoned FNB numerous times, even contacted my private banker numerous times who have escalated the matter numerous times to the credit department. The credit department allegedly has no phones and can only be emailed. How rediculous is this? It has been more than a week now to get the Credit Loaded but no one can help me or give any feedback. Why does my provate banker not have any mandate to assist me? I am shocked at this experience and will be very hesitant doing any future business with FNB.