Being charged for services cancelled last year

I cancelled the services last year in August, acknowledgement of cancellation was made and the technicians came to remove the system. I have since moved out of the house in question, but I am still being charged for services not rendered (from September to November last year and again this March), I was even billed for an annual fee. I have sent numerous emails to their people with no favourable responses, being sent from pillar to post and false promises being made. I am highly disappointed and frustrated at the performance of a company of this magnitude, to make such a callous mistake and frustrate a customer in this manner. I expect to be reimbursed, I work hard for my money.