Thanks for the heads up guys. What I normally do when I don't recognise the number that comes up on my caller ID, I let it go to message bank. If the person is someone with a legitimate reason to be calling, they generally will always leave a message. However if there is no message left, I tend to presume it was a telemarketer and never answer the number in the future.

Annoying telemarketer and also rude.

They are calling and hanging up as soon as I answer, up to 14 times a day.

We will reduce your Testra bill
You need good insurance, you had an accident recently
We are calling on behalf of energy australia, you are eligible for a 12% discount
4, 6 , 20 times a day...

"We will reduce your phone bill."

Telephone telemarketer. We will reduce your bill by some percentage.