90 minute response time for PANIC alarm!!

On Friday 26 February 16:50 I arrived home to find my garage door open. I immediately pressed the panic on my remote. I quickly received a call from the call centre to confirm the call and tell me that an officer is en route. 20 minutes later (17:10) I was still waiting for an officer to arrive. I then decided to request assistance from another security company, they responded within 5 minutes and ensured my property was secure. Later that evening at 18:15 - 90 minutes after my original panic was activated, our gate intercom rang, when I answered it was the ADT officer responding to my panic alarm. I told the officer that this very late response was totally unacceptable, his reply was that it was probably due to shift change. I'd like to know: 1. Why it takes 90 minutes to respond to a PANIC! 2. Why when they do eventually respond they ring the gate bell instead of coming in (access via lock box) to check the property 3. Why you appear to not work/respond during shift change. I find this completely unacceptable. I could have been held at gun point and would have been long dead by the time the officer arrived. This is the 2nd event of poor response in 3 weeks!!