No response to call for help to resolve inaccurate

I have been paying my accounts diligently for 16 years and out of the blue it shows an arrears amount that is not reflected on any invoice. Trying to make contact with someone that can help to resole is futile. This morning a guy came to my house with a JOB CARD (nogal) to cut my electricity. After showing him all my payments for the last year, he apologised and left. Still have nobody from City Power (CoJ) assisting me to resolve the issue !!!