Thanks, but I am now back in Prague and I'll be going to Germany again on Wednesday noon (to Hamburg, Star Wars concert

so I presume I can buy the Fonic anywhere at that time.
So, when I buy the SIM card, I first have to find a WiFi somewhere and activate the card over internet at fonic.de and then I have to call the customer support at 80000 (in German) and tell them to activate the flat data tarif, is this correct?