To cancel ADT security services or any other service agreement, you must issue in writing an statement telling the company providing the service that you are no longer interested in being a customer. A written letter is necessary, as it is tangible evidence of your wish to cancel services. It will hold up in court, and is made even more solid as proof when you present the delivery confirmation notice that accompanied the letter (such a notice is an additional fee and must be requested when the letter is mailed). A cancellation letter is very similar to the standard business letter format.
Use a standard business letter template. This will make the process easier and cut down on the several steps. The template simply shows the proper placement of the letter elements---heading, greeting, body, closing and signature.
Enter a heading on the left side of the page. This portion of the letter shows ADT where the letter is from. Omit the heading if using addressed stationary. The first line of the heading is your street address. Your city, state and zip code go on the very next line and a phone number can be placed on the next line or omitted.
Type the current date as the month, day, a comma and the full year (ex. 2011, not 11) on the next line.
Add the address of the ADT company that you are sending the service cancellation to. Contact ADT if you do not have the exact address. The company has a National Marketing Center that handles such details. Enter the address on the left side. Add the name and title of the person to receive the notice and/or the department. On the next line, type the street address and then suite or apartment on the next line. Got to the next line and enter the city, state and postcode.
Choose a greeting. A simple "Dear" will suffice along with the name of the department or the individual meant to receive the cancellation.
Design the body of the letter. This is where you express your desire to cancel your ADT services. Keep it brief. Some people start with a sentence thanking the company for service. Others get to the point, using the first sentence to ask the company to "please cancel" the service. List the address currently under service and your account number. Offer a phone number or e-mail for contact if the company has more questions or comments.
Close the letter. Most letters close with the word "Sincerely" followed by a comma. Skip a line or two for the signature and type your full name on the next line. Sign the document after it is printed but before mailing.
Business letters are typed and never handwritten.