Support to Anti-theft Service ended 2 years back and there has been several email notices sent to customers requesting to un-enroll the service prior to EOL.
If your device is locked you may be able to retrieve your unlock password through the Anti-Theft web portal through the expired subscriptions link on the subscription page of My Account. Support does not have access to your password.The ability to unlock your device remains unchanged; you will need to enter your 8 character unlock password. If you are unable to remember or recover your unlock password, the Anti-Theft service will follow its design and lock the device. At this point, your only option would be to contact your computer’s manufacturer to request service - in most cases this means replacing the motherboard.
Please follow the instructions and steps to take that Selvan posted in ( Post #10 ). As he basically has mentioned that he is incapable of assisting you personally.
All the very best