Samsung watch not connecting

Lines were added for both our watches. His is paired with his phone, but doesn't work if his phone is off or out of reach. I have been in the store and done a complete factory reset multiple times. I'm at my wits end, being told they have no idea how to fix it. Meanwhile, I'm paying for a service in not getting. I'm at a point to switch carriers. If it wasn't for the lovely young woman at the store I would have already been gone.