Disappointed with FNB treatment of a serious matter

I am sick of getting through to FNB through this platform, I have emailed, I have been called 3 times from customer care to tell me that the revolving facility department is busy with my request, it has been 3 weeks now just to settle, and close an account that is fully paid off. I have no idea why it is so hard for the revolving facility department to get hold of me to fix this very easy situation of a click of a button to close an account that it is blocking me from doing on my online banking. The next interest is due on the 16th and if it asks me to pay the interest amount for it still being open, I will flat-out refuse to pay it and find out who I can escalate this to someone higher up apparently is the only way I can get this very easy task done. I am absolutely disgusted with this treatment, obviously, they are still just trying to take money from me.