SELF EMPLOYED & BLACK - STANDARD BANK WONT ASSIST ME

My name is Sizwe Shilubane, Black male, i am self employed and all my accounts are held at standard bank. i was then contacted by a standard bank representative and was pre-approved for a credit card, fine i completed the application on the app as per instruction received. I was required to send all my documents, which i did. No one contacted me, i then called the bank to follow up and i was told to send my Cipro and Business statements, which i did. a few minutes later, a consultant called to tell me Standard Bank cannot assist me with online app since i am self employed, WOW my rights violated!! she then went on to say i will need a letter from my accountant... I AM SELF EMPLOYED, I HAVE PROOF OF INCOME, I WAS PREAPPROVED BY THE BANK!!!! Why must i be treated differently, is it because i am self employed and black???? I app**** for this credit card because i need it.