Every time I answer there seems to be no one on the other end. And they never leave a message.

A message saying $1800 transaction has been processed against my Commonwealth Bank card and to press 1 if authorised and 2 if not (or similar). I took about 2 seconds to think about it and it then suddenly hung up. Seems very unusual.

Caller: I don't know

Missed call and did not leave a VM. This was one number amongst about 5 others saying from Perth in the space of 30 mins. Don't know anyone in Perth. Blocked.

Caller: Brenda from ANZ

Call saying that a transaction request of $1299 against my debit card. Got the same message last week

Every time I answer there seems to be no one on the other end. And they never leave a message.
https://www.acma.gov.au/publications/2020-02/report/investigation-report-netsip-pty-ltd