Q: Hello  my Iphone Model is ( MC603KS)

The phone is from Sweden. All Swedish phones sold by the carriers are locked. Only one of those offers unlocking.

The model number is NOT a reliable indicator of the locked status of an iPhone. Ask whoever you bought it from.

What does facetime have to do with your original question?

http://support.apple.com/kb/HT4319

I have no idea why you marked your follow-up question as having solved your first question.

Regards.

As Tim said already, only the carrier to which the iPhone is locked can unlock it, and only 3 offers unlocking services. If the iPhone is locked to any other Swedish carrier, then unless their policies have changed very recently, there is no way to get an authorized unlock.

What this has to do with Facetime I have no idea.

No, because it's not locked to AT&T.