Debt Collectors 3 years later

I left Multichoice 3 years ago as i realized the service never worked the way it was meant to, disrupted by weather and never working or nothing to watch. I finally had enough and decided to pull the plug on the mediocre, repeat riddled service. To be honest I do miss the Rugby but the Boks are poor so i'm fine. 3 years down the line I have been harassed weekly by Shapiro Shaik Defries and Associates. They phone regarding R400.00 that's right R400.00! I am not paying it and if there ever was a chance of my return its gone now. I had issues where they told me my decoder was not insured but it was. They made me out to be the bad guy whilst they listened to an hour of my calls only to say sorry you were right with absolutely no compensation for my time wasted. That hour is worth much more than R400.00 . My question is why does it take 3 years to come with a bill? Is your service as poor as I believe. 3 years to come with a bill would make that evident. Lastly DSTV is paid upfront so how exactly am I in arrears. Please resolve this urgently before I make you infamous.