nbn...

Suspect it was telemarketer, no message and for me it was interstate number calling

Got a miscall from this number. When I tried to call back, it could not reach.

I called back and no ringing sound at all and calling ended...

Yes, they call me often. The delay in their starting to talk and the background noise are sure indications of a call centre spamming or telemarketing their way through their allotted numbers.
Also the fact that you cannot call the number tells you that they are "batch callers".
Block them as spam, if you can, or answer the call and just put the phone down and walk away, just for fun.
They'll get the hint sooner or later.

Possible scam/telemarketer

Annoying!!!

I called back number (02) 9052 1606 rang 5 times then goes to busy tone.

Sick of the hang ups

No msg and no details when called back suspect a scam or telemarketer... Anyone else had this number call?