I've got the same calls (my wife picked it up both times and started accusing me of having an affair when both times a female voice wouldn't leave a message or even a name). Knowing Telstra, it's probably them trying to ramp up revenues by forcing victims to block this number. For weeks Telstra was calling me offering money if I go back to them as my fixed phone provider. For weeks I kept telling them they won't have me back even if they were the last fixed phone provider in the world and that they should stop bugging me. So far I declined $70, $170$, $270 and $700 credit-to-my-account offers!!!! The last call was a month ago or so. Hopefully that will be the last I ever hear from them. Oh yes, I live in Perth as well.