Just to clarify JW's post, I think the point may have been lost in autocorrect...
If the system is armed (day or night) and the system is jammed, this will be normal to trigger a full alarm condition.
If the system was unset the system would likely alert like a tamper event, so no bells.
I would assume you have the installers number and it's on a service contract?
Further investigation would need to be done to workout why the system is detecting a jam.