A couple of thoughts. There has been a lot of phishing going on where you get text messages on your phone in the same conversation as genuine myGov correspondence. Except the fake messages include a url which genuine myGov messages don't include. I've received some. People who click on the link can find their details harvested.
It has also happened that someone at an accounting practice has clicked on a phishing email and exposed their computer system to malware which fraudsters use to file tax returns for the accountants customers.
