I am also receiving multiple calls a day from an (02) 8******** numbers. I don't answer because they never leave a voice message. Any legit company that needs to get in touch will leave a message.
These calls started happening after I placed an order online with Kogan.
Or possible when Australia got hacked a few weeks ago..

Caller: Stack market scam artist of Capital Class

Woman calls from a scam company called Capital Class. She tells you she is responding to an inquiry “you” made about the sharemarket. When you ask for her phone number she won’t give you one, when you ask her full name she will tell you you contacted her. She gets aggressive really quickly and tells you she will not stop calling you. I have started receiving phone calls from multiple New South Wales code 02 based landlines.