Remove a activation lock if I bought it from backmartet
Apple Watch
User profile for user:
Community User
The person that you bought/got this watch from needs to follow all the steps on this page;
Remove the Activation Lock so that the buyer can use it.
If they can't or won't then get your money back or recycle the watch and mark it down as a bad experience.
Neither the users on this forum or Apple can help you,only the original owner can help you.