Thanks for all help/suggestions! We will see what will happen now. Sent a message earlier today so we will have to wait and see what they say. But it's weekend now so don't think I will get a reply before Monday.
I forgot to tell one important thing in my first post. They sent me an e-mail about 5 days ago and told me that i have 3 days to remove the game. If I did that I would "only" need to pay the €500, I guess. Unfortunately they sent the message to a mail address I rarely check (the one I used to register the domain). So the time have passed
I will keep you guys informed.