Deliberately missed this call and there was no message left. Checked here and found nothing so called it back but I got "network busy" which it wasn't. So assumed it's a nuisance call of some description. Blocked now.

Didn't answer, they left a silent voicemail, not calling back likely nuisance call.

They called, I didn't recognise number so didn't pick up they left a message which was silent. I rang the number from another phone and got message from Optus to say that the phone has been disconnected.

Caller: Investment seminar

Two calls in two days. But when I called back says number disconnected. Now I am suspicious. They have my name and address.

Caller: Sheffield Pacific

From their website:

"We strive to be a leading company in our core businesses, to empower our staff to excel and ensure continuing customer satisfaction."

Caller: Some tax investment seminar

ignore

Ignored this call because was unknown number. They left a voicemail was just silence. Tried to call back and number was disconnected apparently.

I called back number 0439 279 282 spoke to a woman but did not say for what company.