Bought Apple Watch from Facebook marketplace and it has activation lock. Owner will not deactivate

Unfortunately, there's nothing you can do if the owner won't remove the device from their Apple ID.

Apple won't do anything without original proof of purchase or attempting to reset password.

Activation Lock Support

Hi!

Adding;

Yes, previous post was on point.

I just wanted to make sure; do you have the Proof of Purchase? An invoice? Serial number may be added by hand!

How to remove Activation Lock - Apple Support

Kind regards,

RRD

Two additional options to consider. Contact Facebook for a refund and or contact your Credit Card Company for a refund and let them sort out the issue. My guess is the Credit Card Company will be the best route. Facebook is becoming more and more difficult to contact.

I would suggest in the future to purchase from Apple, as recertified and or other reputable companies. This is an issue when using Facebook marketplace and it is becoming more and more of an issue.