If your ISW13HT is still sim locked after unlock, please do this:
1. Download this file: http://xtc2.net/downloads/PK07IMG.zip
2. Run XTC 2 Tool, open "Flash" tab and select downloaded file.
3. Connect phone in fastboot mode, press "RUU" button and wait for the phone to switch into RUU mode.
4. Press "Flash phone" and wait for completion.