this device was registered with ADM. I went to ADM page and tracked it but location was unavailable. Does this mean that a thief wiped it and put his google account on it? thanks.
Welcome to Android Central! It could mean a few things--the device shut down (either because it ran out of batteries or someone shut it down), wi-fi was turned off, or someone factory reset it. Unfortunately, it is unlikely that you'll be able to recover it--sorry!