I'm having very difficult time with keeping my Samsung Flight II unlocked!  Every time I try to access the Voicemail, it locks on me & there would be no keypad to enter anything on....so all I can do is press & hold the unlock button on the side of the phone & then it still continues to lock.  If it requires a unlock code, I didn't write mine down, so then, I'm "up a creek w/o a paddle"....I guess.  I've checked all my phone settings, & everything is unlocked.  What a mess!