Apple Watch locked to previous owner

The 'activation lock' must be removed and the processes completed by the original Apple ID

owner before another owner can use the item; did you read the article associated with where

you may have started your question here?

• About Activation Lock on Apple Watch - Apple Support

You should return the pre-owned/used watch to the big box store where you bought it and

have the management refund your purchase price or exchange the item with an unused one.

The instructions in the page link above apply mostly to the original owner before giving away, etc

of the product, similar to giving away or selling an iPhone or nearly any other Apple product...

Turn off Activation Lock before you send your Apple Watch in for service, sell it, or give it away

Before you send your Apple Watch in for service, sell it, or give it away, you should turn off Activation Lock

on your Apple Watch. Just unpair your Apple Watch from your iPhone:

1. Keep your Apple Watch and iPhone close together.
2. Open the Watch app on your iPhone and tap the My Watch tab.
3. Tap Apple Watch, then tap Unpair Apple Watch.
4. Enter your Apple ID password. If you forgot your Apple ID password, you can reset it.
5. Tap again to confirm.

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. On a computer, go to iCloud.com.
2. Sign in with your Apple ID, and open Settings.
3. Under My Devices, click your Apple Watch.
4. Click X next to your device.
5. Click Remove to confirm.

Anyway, sorry that there appears to be little or nothing I can help you with at this end.

Good luck in your discussions with the people where you bought the watch...! 😐