Number calls through then hangs up upon answering

I received many times phone call from this number (02) 9191 5885 during last two weeks. It calls me every day but never speak. I though that it might be involved a fraud. Please check for me.
I can be contact on 0433 704 145.
Thank you so much.

Has called twice in last two days, hangs up as soon as I answer.

number calls and hangs up straight away

Calls an hangs up

When I answered they hung up

That number calls through and hangs up when you answer it. Very annoying

Westpac