Chubb (non)cancellation of contract

I submitted a request to cancel my contract last year July 2018. Since then I have been spammed with multiple letters and calls demanding payment after I eventually stopped the debit order myself in December last year. The alarm has never worked properly and when trying to get someone to come out and get it to work - I was told I would have to pay a call out fee, which I find insane. This after multiple sms's just casually letting me know that the monthly fee will be going up. You are more than welcome to come and take your alarm - it doesn't work properly and I am no longer paying for a service that I haven't received since July last year. I am also not paying R2000 because no one went through the effort of processing my cancellation. Even after 2 phone calls where I was told that the cancellation has now been processed!

I am not asking for a lot, please can someone urgently assist with this and not just tell me it has been resolved so that I can get spammed 2 days later.