Calling Xfinity Voice get message "Wireless customer not available"

I'm really done dealing with Xfinity's customer service. I've spend so many hours on their chats, and phone calls trying to rectify problems, or start new services. It is painful to deal with you. 

And now...the new phone line I just put in a few weeks ago, and had to spend hours with you getting to work, cannot be called. Constantly getting the message "The wireless customer you called cannot be reached" or some such thing, even though this is not xfinity mobile service. 

My mother in law can't log into her bank, or any of the numerous things for which she needs to get a verification code bc she can't receive the numeric code, because you can't call the line. We got this line so that we would be able to reach her...and we can't.  Internet works fine....phone does not.