cannot unlock this iphone5s

Hi cherngfromjohor bahru,

I apologize, I'm a bit unclear on your exact question. If you are saying you can't unlock your iPhone meaning you are having an issue with the passcode on the lock screen, then you may find this article helpful:

iOS: Forgot passcode or device disabled

http://support.apple.com/kb/ht1212

If on the other hand you are talking about unlocking to use with a different carrier, then this article may be more useful:

iPhone: About unlocking

http://support.apple.com/kb/ht5014

Regards,

- Brenden