Bad service from ADT

I have cancelled my agreement over a year ago due to the high pricing after being with this co for many years. Only after it was cancelled I had numerous calls from them and now after a year received a notice if outstanding money after they incorrectly put a debit order thru on my account. I called and sent emails but as usual their service is bad as no one has rep**** or cone back to me with regard to my complaint and their claim of outstanding money !! With this maybe someone will call back!