Insurance Co. Jacked up rate when discovered alarm system removed

[Edward R.]

So I renovated a property last fall/winter and had an alarm system put on it (simply Safe).  Then in April we switched the policy to Metlife and still had the alarm and stated so.  Late may/Early June we removed and then canceled the system.    TODAY, received a letter from MetLife "YOu have removed your protective device thus you premium is changed"  now it's $82 more per year; It was only $450 before that.  We removed only because renters were now in there.  never realized insurance would jump that much.  

First; How did the know?  SImply Safe  alerts them? 

Doesn't that seem like a huge jump?

Do you guys get a discount if you used a non-monitored device?