I called back number (02) 4302 6963 reached voice mail but did not say from what company.

Sydney caller did not speak when I answered the call. Stayed on the line for a few seconds and hung up after my 'hello". On returning the call, a voicemail message states 'Thank you for calling, all of our agents are busy ' and ask for your name and number so they may return the call. Sorry if your organisationn's voicemail won't identify you then you're being placed on my auto reject list.

Whoever this is, they do not leave a message, but just waits on the line for about 5 seconds so that it registers and I pay to retrieve a blank message!

interstate caller that didn't leave a message