Terrible service from ADT

Our alarm has been giving issues since Monday. We reported this to ADT and had to log a call for a technician to come and repair. They advised that they are fully booking till Thursday. They then said they can send a technician at 17:00 which is on standby. They said they will call me and advise on the status. They then called to say that a technician will arrive between 17:00 and 18:00. The technician then later called and advised that he will only be here at 18:30. He worked on the system and it was working when we left. Only to get back to our office and it is again not working this morning. You pay overtime just to have a system that is not operational. They delay getting to you and then do not fix it properly.