Need a fourth line for our apple watch

We have been trying to get an apple watch connected for over 6 months. We currently have one of them with a standalone number on our plan, our phones and watches are ours (we brought them to the plan, we did NOT purchase them from xfinity). So far we are hearing different stories on 1. call the credit reporting agencies .. which makes no sense, they just provide a report, this is an xfinity process. 2. wait.. we have been. 3. It's some government agency outside of xfinity (different from the credit reporting one) and have to call them.. to me this seems like xfinity is doing everything they can to make us buy a device from them to get a watch to work on this plan.

This feels very dishonest, we keep hearing the same stories that make no sense. Everything is an xfinity policy... and there have been no straight answers on the reason for this.