This is a bit of a saga and there is more video explanation of this story that you will find on the Aussie Cossack YouTube channel.
https://www.youtube.com/c/AussieCossack/videos?app=desktop
After taking $655 million, Ukraine orders Australia to ban Russian tennis players! - Aussie Cossack
So the Aussie made a call to the Ukraine Ambassador just to have a chat. You will find the video on his channel but the next thing you know.
Australian YouTuber reported to police by Ukrainian ambassador over alleged 'harassment campaign'
In a video posted to YouTube, Simeon Boikov - also known as 'Aussie Cossack' - made a prank call to Ukraine's ambassador to Australia Vasyl Myroshnychenko.
https://twitter.com/AmbVasyl/status/1610928576475590657?s=20&t=nJmn8QuMVBAyqLtXbnKxgw
https://twitter.com/AmbVasyl/status/1610928576475590657?s=20&t=nJmn8QuMVBAyqLtXbnKxgw
Now the Aussie has released a video giving a situation update also Boikov (Aussie Cossack) said he was seeking legal advice (in the description in the video) over a tweet Myroshnychenko (Ukraine Ambassador) published which claimed Boikov had links to Russian intelligence – an accusation he denied and labeled defamatory.
So possibly after talking to the Ukraine Ambassador the Aussie Cossack will now have links to Ukrainian Intelligence. Is this the type of logic the Ukraine Ambassador is using with the Aussie Cossack and his background or is he keeping information away from the Australian Government? Why is he making a Twitter announcement is he does?
That would be a matter for ASIO.
9 Jan 2023 - Federal Police snitch Myroshnychenko - Aussie Cossack