Hello, my friend from Germany bought an iPhone6 in the US while being on a student exchange program and activated it with a Verizon prepaid card. Recently, after returning to Germany, the phone was broken and replaced by a local German Apple store. After that, the initial activation was done through WiFi, with the Verizon prepaid card inserted. Now, it's not possible to enter any other SIM any more, we get always stuck at the message 'SIM not supported'. I can only imagine that the initial activation through WiFi somehow locked the phone to Verizon, since it was a vanilla German phone in it's sealed package.
Question is now: how to remove this lock? The original prepaid phone number is meanwhile deleted (I suppose due to inactivity), so there is no way to get anywhere on the prepaid support number.