I use to get this type of calls with 07 area code, now i get them from 03 area code. Apparently overseas scammers have worked out how to set up a network of numbers in your country and call people from God knows where through local numbers. So far each local number is used only once to avoid detection. Every time i called back the message was, ''the number is disconnected''. Next time they call the number is different.

I get regular calls from numbers ranging from (03) 9912 4800 - (03) 9912 4808. They keep trying from different numbers within this range. The first time I answered, they didn't respond after 3 hellos, so I just hung up. They keep trying with the other number variations. No message is ever left. I just keep blocking each one after they ring.

GAPbuster.

They have never cancelled any of my assignments.  They usually phone people when they have premium payment assignments.

Got 4 calls in quick succession, none of which I answered.  Who are they?

Yes, it's Gapbuster. They are a mystery shopping company. I think they are based in Australia but have work internationally.Watch out for them. They cancel assignments AFTER you have done them and so don't pay you - either for the job or for the expenses/purchases.  Tread with caution if you go anywhere near these guys.