The service menu unlock was disabled in MF3. You have to get an unlock code from your carrier or another service.
Sent from my SAMSUNG-SGH-I337 using xda app-developers app
Current Device: ATT Samsung Galaxy S4 (i337)
Droid Bionic (GSM Hacked)
HTC Inspire 4G (Desire HD)
HTC Dev Phone 1 (Dream/G1)