Why is your administration always so bad

I had 2 properties with ADT. One was my private residence and one at my business. I sold my private residence in 2017 and canceled with ADT. In May 2018 I also canceled my business account as that property was also sold. Now in July 2018, I get a notification with ITC that there is an amount owing for R 1,500 with ADT. I phoned ADT to have the matter resolved and even though I don't owe them anything nothing happens. I have since escalated the matter and contacted them again and still, nothing happens. I am seriously unimpressed that your bad administration (Something that I had to take all the way to your CEO in 2011), is now influencing my credit rating. I expect this matter to be cleared within the next 48 hours and a letter stating that everything has been resolved or I will be forced to take the appropriate steps.