Sent it to voicemail but no message left. Checked the number with Cybertrace and it is 66% likely scam.

This number called me purportedly from the Fraud dept of Commonwealth Bank. Caller said that my account purportedly has been put on hold pending a potential fraudulant transaction. I said that I don't have a Commonwealth Bank account. He said "Yes I know you don't have a Commonwealth Bank account, but I think you have a Westpac One. We are trying to stop a fraudulant transaction". I asked what was it for and the amount. He stated "Maryland in the US for the sum of $US499". He then asked did you authorise this transaction. When I replied No, he said, I know need you to transfer you over to my ANZ colleague. At that point I twigged that he was a scammer. I said: "no, don't pass me on to your colleague. I know you're a scammer and I hung up.