Cannot set up cellular on Apple Watch

Recently switched to Xfinity mobile from T-Mobile. Cellular has been removed from T-Mobile now trying to set up Xfinity mobile. The message I get is the phone you’re trying to pair with the watch is not on your account. But it is. I contacted Xfinity mobile representatives and they don’t know what to do. I contacted Apple representative. They don’t know what to do. Please get a hold of the CEO to resolve issue.