Don't recognize number so call not answered

Caller: Indian guy called Harry

He said he was Harry from NBN. You have had an issue with your internet over the last two days (which is not correct) I said how do I know this is not a scam. He said I have all your details. I said who is my provider? He said Optus (which is also incorrect) I said no it isn't. He said You are a liar. I said goodbye and hung up. When I called the number back it was for some charity. A loud whistle is required for this number.

answered the call and i got a machine message , it started a message about visa so i hung up. scam.

Didn't leave a message.
Suspected scammer - all these dodgy phone calls tend to come around either midday, 2pm or 4pm.

Caller: I don't kniw

Says hi I am David then hangs up. Number not know to me. Certainly not an acquaintance called David

SCAM CALL - a heavy Indian accect claiming to be from NBN to upgrade internet by installing software. When I asked questions they hung up.

They hung up as soon as I answered. I would like to blow a whistle down the phone of calls like this but I have been told its illegal.

Spam

A similar number often calls always at a bad time when I called back my call was '' barred ''

I get one of these each morning, i dont answer them as i have a answering machine, if its a genuine call they leave a message, these scam calls just ring and hang up, at times i am tempted to answer and give them a piece of my mind but that just makes it worse, i agree with one person on here, a loud noise in their ear.

Unknown number, answered and no answer. Said hello and they hung up. 100% scam, do not answer.