Hi @Jacek and welcome to our forum! If this concerns a new connection, have you checked the confirmation of your order yet? In there it says when the services will be activated. From that date on, when the KPN Box 12 has been connected, you should have a working internet connection. If you hook up the Box 12 before that date, the services won't work. 

If the connection date has passed already, could you fill out your forum profile with the name + date of birth of the subscriber and your address? If you notify me here that you’ve done this, I'll be able to check what's going on with your connection. 

I haven't heard back from you, so I hope you have a working connection by now. If not, don't hesitate to let me know!