Caller: A robot on behalf of a telemarketer

Telemarketer that uses an auto-dial to patch "hot" (answered) calls to a human agent, and/or logs the active number. Quickest way to stop this one number is by blacklisting it in your phone, and if you want to stop most telemarketing then register your number on the do not call register donotcall.gov.au

Have called a few times, no message. Called again just now, message 'hello...hello'
I have not called back. thanks everyone for the comments