strange electronic voice saying they are investigating me for tax fraud

Electronic voicemail stating I was under investigation and that court action against me had commenced
Upon returning a call to this number, call was disconnected after 2 rings

this is scammer I have checked with the tax dept all is ok hung up strait away please investigate the people .

Caller: supposedly the australian taxation office

auto message to start saying I was being investigated for fraud and a lawsuit was being opened, I called back and was asked for my info, I asked for their info first to make sure it wasn't a scam, he rattled off some case number but when I questioned it further he hung up.