This number calls you from a call centre saying they are from Telstra Big Pond in Sydney Australia. (although all of the operators speak Asian). They say that there is a problem with your ISP and they are detecting warning messages from your ISP and they want you to confirm details.
When you probe them from where they are from and their number they become quite allusive. When you tell them you don' t have big pond they hang up. The number is always engaged and you can't call back. Don't give them anything.