Many commentators seem to believe this. You can even find a comparison video on YouTube that conclusively 'proves' the theft.
What Mr. Producer has done basically is write a song over Arty & Mat Zo's track. He has released the song without permission, and therefore he is a song thief.
What a load of utter tosh!
What has happened here is A&MZ have created an instrumental dance music track. It's pleasant, but nothing to rave about. And in common with a tradition going back many years, Mr. Producer has used this as inspiration to create a song. This is happening on a day-to-day basis in both professional and amateur music making all around the world. Nothing to see here.
What would happen next normally is that if the song is deemed worthy of release, the label would approach the original writers of the backing track for permission to use it. Payment would be negotiated, the track would be released, sales would be made. Money! Everyone's happy. Situation normal.
But apparently in this case Mr. Producer has STOLEN the song. News outlets are in a frenzy to report that something terrible has happened and Mr. Producer is a really evil person for doing this.
What may have happened is that the song has been released without the rights to the backing track being properly acquired. That could possibly happen through oversight, or not seeing the legal process fully through to completion.
But I doubt it. I think that the whole thing is a massive publicity stunt for both Mr. Producer and Arty & Mat Zo. And the news outlets know this. There's only so much real news happening each day and there's nothing like a celebrity scandal to pull in readers.
If you like the song, then buy it. If you like the backing track, buy it. But don't get taken in. It's all part of the publicity game.
P.S. If Mr. Producer approached you to use one of your tracks, would you refuse? I suspect many people still toiling unrecognized in their home studios would let him use their track in return for a credit and no money at all!