Strange account in family management made a purchase!

Wizga

So I receive an email that I have made a purchas (a game called Fullblast) and that a child account has been made. I call my brother to see if he's messing with PS4. Apparently no. I panic and change PSN password. I arrive home and see that 5€ are gone from wallet and that game is nowhere to be found in PS4 and there is no history of me buying it.

I check around the web for solution and find out that a strange account named  Tuulimyllyntie in my family managment has bought it. How that account get there? What is going on? Am I hacked?  What to do? I don't want to loose more money.

Trollslayer

I would say so, the name looks random as well.