If there is something wrong with your ADT system and it was installed by an Authorized Dealer, like Zions Security Alarms, if it is in the first 90 days you will want to call the dealer directly. They will come out and fix any issues without any additional cost.
If it is after 90 days, ADT will service your system. Call them at 1-800-238-2727.
Most ADT customers have something called QSP (Quality Service Plan). It is also referred to as a Limited Warranty in their contract. This means that if something stops working from normal wear and tear ADT will send a truck out without parts and labor costs and only a $25 trip charge. Most companies now-a-days charge $50 for a trip charge so ADT is one of the lowest priced for service calls if you have this warranty included in your monthly rate.
Those customers that do not have a warranty on parts and labor have two options if they need a service call. Pay ADT to come fix it which starts at $150 for the first half hour, or call around and see if you can find someone else to fix their ADT system.
If you replace windows or doors or do anything else that would cause your alarm to not work because of something you did it would not be covered under warranty. Some people change their phone service and then the alarm is not connected. If you do this the correct way your phone service will make sure the alarm works before they leave your home. If you do it the wrong way you will need to pay for a service call. (No bueno)