Abusive guy now harassing me on multiple numbers

Looks like there are multiple numbers. 4820, 4821, 4826. When you ring back the numbers are not connected. WTF?

constant calls from (03) 9912 4837,4838,4820,4807,4803
the number does not work to ring them back and they do not leave message.

Caller: (03) 9912 4820

Picked up but no one answered. Call ID says potential fraud/spam

Caller: (03) 9912 4820

The guy mentioned my name and then mentioned some financial transaction - I said I didn't know what he was talking about and he hung up.

TrueCaller app mentioned that someone looked up my phone and probably this is where they've got my name.

Says it's Caveo Communications - possible fraud. I did not answer, just blocked it.

I called back number (03) 9912 4820 rang once then gets disconnected automatically.

This is a scam number. Indian people say they're calling from London, even though the number is Victoria. Some "financial" service and about a "financial transaction" that I have recently made.