Discovery insure doesn't honor DQ track appointmen

There was a DQ track installation appointment set up on 10 Dec 2015 which Discovery Insure didn't honor. An email confirmation was received from them for this appointment, but there was no specific time of day set. I was only told that the installation will take place before 16H00 on the day. I then gave them a benefit of the doubt and set another appointment for the 15th Jan 2016. Another email confirmation was sent and a call center agent called to that the installation will happen before 12 noon. Discover Insure then moved this second appointment from 15th Jan 2016 to the 18th Jan 2016 before 12 noon two days before the day of the installation. To my surprise no one showed up again on the 18th Jan to do the installation. There was no notification whatsoever to move the appointment or to give an form of update. I really find this kind of service quite appalling. I'd appreciate some form of communication if there's any changes to appointments. I demand an explanation and a resolution to this situation with immediate effect.