No assistance

I have had problems with ADT's billing since I installed an alarm system last year October. I live in a security complex and therefor qualify for a lower monthly rate, but they keep on putting debit orders through for a higher rate. I sent emails, but no response, then I stopped payments and also no response until another debit order for...wait...the HIGHER rate again went through today. I AM FED-UP AND DO NOT WANT YOUR SYSTEM IN MY HOUSE ANYMORE. PLEASE CONTACT ME TO MAKE ARRANGEMENTS TO COME AND REMOVE IT ASAP!