Which embassy or consulate should I go to for renew my passport?

Hi, I am from Adelaide. My passport is going to expire next year march,
Recently I been down to Melbourne Branch ( Consulate General), and they told me that I have to do it myself, so I sent all the supporting document to Hong Kong and they told me I could do it in AUS. So I called up the Chinese Embassy in Canberra, and let them know the stories. And they said Melbourne could definitely do it. So now I am bit confused with both stories.

When I was there (Melbourne), the receptionist and the teller lady said to me, you have to do it yourself. While I am doing it and send to Hong Kong, they said I could do it in AUS.

So anyone could please answer my question. Lots of appreciation, and thanks for your time.