have received calls from this mobile number 0402 198 759 long delay after I answered so probably dodgy

Long delay before receiving any voice. They claimed to be doing a survey on Solar Panel installations.

Very persistent caller. I let it go to answering machine. Have told them I have panels installed. They still call. :(

When my mother told her not to ring again she said I will keep ringing you and will tomorrow and then hung up. Was for solar panels

Persistent. Obnoxious. Rude.
Solar panels?
Where do they get our name & unlisted number?
If your name really is "Anna Wilson" then shame on you for unsolicited calls, rude and petulant behaviour.

This number called tonight and they hung up. I called the number back and it said it was disconnected by an automated message from Optus

I didn't answer call

Answered the call. A long delay. They hung up. I rang straight back and a recording says: "OPTUS wishes to advise that this number is disconected."

Received a call on the land line today from this number, called it back, and it was an automated Telstra message, that the phone has been disconnected.
Can't understand how the number was disconnected after calling my number half an hour earlier.

persistant Bullsh*t.

Long delay then the call disconnected.

Have had this number ring. A few times and they just hang ....redial and no response!

keeps phoning hangs up before answering machine kicks in

This number has been disconnected as far as I can tell

I had a missed call from this number 0402 198 759, on returning the call was informed by an automated voice that the number had been disconnected, strange.

Got a call from that number at 8:15 pm. Couldn't understand what the man was saying. Had a very strong foreign accent. So I hung up. Best thing to do.

If you try calling that number you'll get an Optus message saying the number is not connected. I don't think it will get traced too well.

Received a call from this number today. Firstly, I couldn't understand what the gentleman was saying. Then he wanted to speak to somebody who doesn't live at my house. I hung up: that's the best treatment for such callers.

Something about latest on solar panels. Asked if I was the home owner (we live in a unit) and when I said no (untrue) the girl rang off.

I received a call from this number today. They want to talk about Government incentives on Solar Panels.