ADT Worst Security Company

My parents have been with ADT for over 18 years they then cancelled 3mths ago as they couldn't afford the premiums as they are now pensioners. They joined up with a cheaper security company. ADT's alarm was taken out but ADT still debiting my dad's account every month with over R700. This is ridiculous! Do not join ADT you pay for years the alarm is never yours and when you cancel they refuse to stop debiting your account.