Rang my mobile and then hung up

Rang my mobile and then hung up.

rang and hung up

Who is this

something about unpaid electricity bill. then the phone cut out.. I have never had my name on a utility bill...
I tried to call them back - optus advised me number had been disconnected..

same, ring and hang

Same - the number is registered coming from Croydon VIC

Same - never left a message

Rang mobile and did not leave a message

Rang my mobile and then hung up.It showed me calling from Croydon, Victoria.

i didnt answer but did a call back straight away and got the message "optus advises that the number you have called has been disconnected"...strange

same thing for me around 12:22 on 12th April