If the phone has been locked, then the first thing you can do is enabling the data services. While the phone is at the lock screen, press and hold Power until the menu appears. If it's possible, select Data Connection. Input the pin as many times it's necessary until you are prompted to enter the email. Add the email attached to the phone and then you will receive a PIN. Enter the pin from the email (PC or another device is required) and you should have unlocked your phone.
If it's not working, turn off the phone, press Volume Up + Home + Power. Enter recovery mode, select Wipe data, reboot phone and the password protection will be removed.
Note: This operation will delete games, apps, and custom settings.
