They've been ringing the past couple of days, before that the number popped up from time to time over the course of 6 months or so, I don't know this number so I won't phone back.

I just received a call from (07) 3547 7160 as well. The line was automatically disconnected once I answered the phone.

I called back number (07) 3547 7160 rang once then gets disconnected automatically.