Calls from this number hang up when I answer. When I call the number, it goes straight to hang up. Sounds like telemarketers or a scam.

Has called several times in one week but no message.

Complete NUT does not even leave a message

This looks like a scam.
When it reached the Telstra Call guardian message they hung up.
The extra cost of the call guardian has stopped dozens unwanted calls.
The only problem you just have to let the phone ring until the caller listen to the message and then you press a button if you want the call or another button to block calls from that numer..

I called back number (07) 3623 1616 reached voice mail but did not say for what company.

I just got a call from this number. No message. I rang back, just kept ringing.

missed call from this number and when call back rings twice and cuts out

I called back number (07) 3623 1616 rang 2 times then goes to busy tone.