Bought an Apple Watch that is still linked to old owners account

Hello ~ That is the activation lock. If the person/persons that you bought the iPhone from cannot or will not remove it …the iPhone is basically useless to you. If they cannot/will not remove it…return it and get your money back. We cannot help remove it nor can Apple. Take a look here:

Activation Lock for iPhone, iPad, and iPod touch - Apple Support

Also:

The All Too Common SAD Reality of Buying a Used iPad/iPhone

~Katana-San~

Return it and get your money back. there is no way to bypass the activation lock. Only the owner of the account it's locked to can remove the lock.