This is a scam, the caller used a computer recorded message to threaten action on a debt owed to the ATO.

As previous comment this was a message threatening warrant for arrest.

Caller: David foster

Threatened me that ATO filed a case against me for owning $6k . When I wanted a paper document he said I have two options either pay the debts or hire a lawyer to fight the case.

Computer generated American accented voice threatening an arrest warrant if the call is not returned. Scam!

I called back number (02) 8006 7668 rang once then gets disconnected automatically.