Upgraded In Error and Inability to Downgrade

I recently went onto FNB's Online Banking to Change the limit on my credit card. I did this and instead of my limit changing correctly it changed incorrectly and my credit card was upgraded. This I did not request and did not sign up for. I have since requested my credit card to be downgraded but this is not possible. My old credit card has been deactivated and Sam Maabane my supposed private banker cant or wont help me fix the problem. <br> <br>