Missed call. I didn't click on the Voicemail they left, but according to the text transcript, it was garbage wording and clearly either spam or a phishing attempt.

Claimed to be from Mastercard, or Westpac Mastercard. I can find no link between them and this number. Knew my name (first name, at least) and state. Claimed there had been a possibly fraudulent charge of $600 to my Mastercard, on Amazon - within the last few minutes. I had a near identical call from (02) 7268 9862 the following day. Both times, after I questioned their legitimacy, they hung up. Have reported to "hoax @ westpac.com.au", but don't know what if anything they will do about it.