Knowledge Base
After processing your iCloud unlock request, you can finalize unlocking your iDevice by restoring your device via recovery mode.
_To prevent the Activation Lock option from being activated again on your device, be sure to restore your device as a new device via recovery mode.
_Warning: Restoring a device as a new device via the recovery mode will delete all the data it contains. This data includes, but is not limited to, purchases made in iTunes and the App Store, content stored in iCloud, and all Message conversations.
To learn how to restore your device via recovery mode, please see the article:
https://support.apple.com/en-gb/HT201263
Do not restore the device from an iCloud or iTunes backup. If the device is restored from a backup, the Activation lock option may be activated again !