Silent hang-ups after picking up often signal scam attempts or automated robocalls probing for active numbers. In this case, the caller dialed an Australian line and disconnected immediately, leaving no message or interaction. This pattern raises data protection concerns, as such calls can lead to unwanted data harvesting or escalation to more aggressive tactics. Advise blocking the number right away and registering with Australia's Do Not Call Register to cut down on these nuisances. Monitor your phone for patterns, and never return calls to unknowns—report persistent issues to the ACMA for investigation.
I received a call on an Australian number, which was disconnected as soon as I picked up.