LOCKED

My grandparents locked themselves out of their iPad. The only screen to come up now says that the iPad needs Activated using the Apple ID, great! Type that in and it says "(email) cannot be used to unlock this iPad" Upon looking closer at the Activate iPad screen it says, "This iPad is linked to an Apple ID. Enter the Apple ID and password that were used to set up this iPad. (email)" The email is not the email that associated with this iPad. It's close, but not correct. I have no idea how it got locked out under a similar but slightly different Apple ID. How did that happen? I bought it with my grandmother, brand new and helped her set it up and left them to it! Can any one help me? I also looked into iCloud and iTunes without success.