My girlfriend just got her phone back, she doesn't remember her phone lock, is there a way to bypass it?

Do a Samsung Master Reset:
CAUTION: A "master reset" changes the phone settings back to default. This process will erase all contacts, downloaded settings, and downloaded applications (ringtones, wallpapers, graphics, etc). This process cannot be undone.
Enter *2767*3855# from the standby screen. (You may need to remove the SIM before it will allow you to type the code in)

No have her try notifying provider