Account suspended and not my fault

Due to a unfortunate event I had to do an early upgrade on my contract for a new phone. I went to the Telkom branch in Easgate, did everything and requested that the early fee was split over two months. I was told it's fine and the proceed to log this. The month after, my account was suspended because I had "exceed my credit limit". To be clear the full amount required on my invoice was paid in full and on time. When I enquired about what was wrong they explained it and said it will be rectified. In 48hours my account was working again. The following month the exact same thing has happened again. I called and explained. Another case was log over a week ago. And after multiple follow ups I still have no feedback on what is happening and zero help, very unsatisfied.