I have a used Apple Watch and cannot comple set up due to incorrect Apple ID

The person that you bought this watch from needs to follow all the steps in this link;

Prepare the watch so the buyer can use it.

If they can't or won't then get your money back or recycle the watch and put it down to experience.

I have the same issue with a watch i bought used. Since there is no way to unlock it. How would i go about recycling it?

Take it to an apple store.