Help remove activation lock

The Apple ID is the same as the one you use with your paired iPhone.

You can recover your Apple ID by following the steps in this article:

If you forgot your Apple ID - Apple Support

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If you can't access your iPhone or Apple Watch, or if your Apple Watch isn't paired with your iPhone and you need to turn off Activation Lock:

1. Go to iCloud.com and sign in with your Apple ID. 
2. From the Quick Access Menu in the top right, select Find My. You might be required to sign in.
3. Select All Devices, then click your Apple Watch.
4. Click Erase Apple Watch. Select Next until the device is erased.
5. Click the remove button  next to your Apple Watch.

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copied from: About Activation Lock on your Apple Watch - Apple Support

If you have proof of purchase, you can contact the official Apple Support by starting the Additional Support Process for the Activation Lock:

Additional Support - Activation Lock

Are you stating that you have more than one Apple ID? More than the ID that you used to sign in here?

Activation Lock prevents lost and stolen watches from being used by others. There is no way to circumvent the Lock.

An Apple Genius Bar may be able to help you if you take the watch, your photo ID and the original receipt in your name with the watch's serial number to an Apple retail location.

Activation Lock removal -

How to remove Activation Lock - Apple Support

M1 Mac mini, macOS 14.1;  Watch, series 7 GPS/cellular, watchOS 10.1; iPad Pro 2nd Gen, iPadOS 17.1; iPhone 12 Pro, iOS 17.1; TV 4th Gen, tvOS 17.1; HomePods, audioOS 17.1 and Airport Express w/ Airplay 2