It's an automated system that dials random numbers. If the call is answered it automatically hangs up and relies on you to return the missed call. Once you call the number back they have you. Any number I do not recognise I save on my phone with the name DNA (do not answer). If the number calls again I see the callers name as DNA and I ignore it. Experience is the calls stop coming after a short period of time. The trick is not to call back. If it is important the caller will leave a message.

I have been getting the same call from the same number for the past 4 weeks! Call and then hang up.  

Received a call 29/11/13 for income protection insurance

contacted by this number today - ANZ Life insurance I have no idea why they would calland during work hours

Kindly have this company cease calling me!

It's ANZ. I called the number back, pressed 2 and waited until a service guy/girl answered then hung up on them. I'll keep doing it for every call i get and so should you all!

Call received, answered, immediately hung up