Unknown number called. No message left presume spam & number blocked.

Caller: They hung up

Obviously a probe. They are using numbers in the (03) 9967 6102-(03) 9967 6106 range. Call back is to non-existent number.

This number has called me three times in the last hour. Once was on my personal number, which my phone automatically blocked as spam, and twice were on my business number, which when I answered, the call was immediately ended.