When a tablet is unlocked, the easiest way to remove the lock is through the RESET button. It will wipe all the custom settings and installed applications but then it will give you an access back. Almost every tablet has a RESET button. Locate the RESET hole and use a sharp pin to press it. Wait a few seconds and the tablet will restart. During this time it will return to the factory defaults. When the process is finished, you will have an access to your tablet. You might need to re-attach the Google account and any other account for the services you use.
