I called back the number (03) 9872 3481 and reached vm but couldn't hear the company name

Caller: dust masters

They will never stop calling

I answered call without speaking, the person on the other end also did not speak (perhaps waiting for me to confirm answering the call) but I could hear other voices in the background, they did not announce who it was. After some silence they hung up. I'm not calling them back. I think a caller should announce themselves first, otherwise they don't know who they are calling.