I know this might be too late for you now but I just had this happen to me so here is how to unlock your phone.
On a pc go to https://www.google.com/android/devicemanager and press lock, it will ask you to type a new password when you set this it will change the lock screen on your phone to the new passward enter that and there you go!
When i tried through device manager, it allowed me to set new lock. But once done, it said "your phone is already set with a lock, you wont need this new password to unlock" the new password is not overriding the lock on my phone. Can you help?