The worse customer service I have ever encountered. Have not serviced my alarm system for 3 years. When I finally booked an engineer ADT cancelled 3 times without contacting me and me having to contact them every time. When I was guaranteed a 10am slot I called at 930 to be told early afternoon thay day. I ha e not taken 3 mornings off work to hang around for an engineer that didn't come. The customer centre is always polite but do t seem to know anything at all. Writing to the CEO made no difference. I will not be renewing my contract, having been with ADT for 7 years. So very disappointing. I would not advise ADT as an alarm system to anyone as their customer service is non existent.