Harassment for cancelled ADT contract.

Wish I could give a minus 5-star rating. I have been harassed by this company for an ADT alarm contract I cancelled SEVEN months ago. Account JOO00578. I have never had a call from ADT, nor an invoice, or statement of account sent to me for the outstanding amount of R158.04. I have no fewer than 7 email exchanges between myself and ADT wherein I struggled to get them to acknowledge cancellation. I also have proof that I cancelled by giving way more than 30 days notice. I refuse to pay for a service I not only did not receive, but which was cancelled months ago. I will approach whatever Ombudsman I need to, or will engage my own legal counsel if this matter is not withdrawn immediately.