Adt Security
CANNOT CANCELL SERVICE

I have been trying since 20 May 2013 to cancell my service with ADT. I have sent Faxes, Emails, made phone calls, switched off the alarm since 2 June 2013. They refuse to phone me directly, just send SMS saying I must contact call centre. Been there done that... They just keep deducting form my account every month.
I took out my orginal contract and sent a fax to the number on the contract, no reaction.