tablet google locked

[AC Question]

My sons girl friend google locked my tablet. I do not know the password or e-mail used. It keeps saying "This device was reset. To continue, sign in with a Google Account that was previously synced on this device." The store has been no help at all. They say they do not know how to fix it, Does any one here know how to fix it? My son an her are not to gather any more, so no she will not unlock it.