An ATO employee just messaged me personally and asked me on a date, how do I report this and to who?

Just what the title says, a guy I've never met before messaged me on my personal phone number, addressed me by my first name and invited me for drinks at the suburbs I live at. I arrived to Australia less than 2 months ago on a WNH visa and I'm married, guy claimed I gave him my number at a bar I've never been to.

I did some research online based on his number and found out he works at the ATO, which is how I assume he got my information from. I confronted him about it and he started insulting me, so I blocked his number.

Lodging a formal complaint on the ATO website would be enough or should I contact other authorities? I'm quite shaken up by whole situation and frankly I don't know what to do. Any advice I could get would be very helpful.