Called me twice at 3am in the morning!

Calls about once every two weeks about 2-3 times @ 10PM-11PM.

No voicemail left, so must not be important! Have not bothered to call back.

Caller: North State Security

They will call you if you are on the call list for an alarm going off.

Caller: (03) 9831 0887

Calls at wee hours of the morning. They left a message Stating that alarm needs servicing. Indian call centre when called back. Either way I would treat as a scam

Caller: Security company

This is the national centre for Bluelight Security. They have your number as a contact for an alarm somewhere that hasn't been set or hasn't been activated after hours. Call Bluelight security and get them to take you off their contact list.
Good company just doing their job.

Called at 0650 and didn't leave a message. Tried calling back but no answer.

alarm company

Two phone calls in the middle of the night. I hung up the first time, let it ring out the second. No message left.

I called back number (03) 9831 0887 rang 5 times then goes to busy tone.

This is the national centre that takes care of alarms. If an alarm is not set or goes off they call the person listed. If you get a call from then and you're not responsible for an alarm system, then someone at your work has registered the wrong number.

I called back number (03) 9831 0887 reached IVR for a company called National Operations Center.