Xfinity Authenticator app - unable to complete setup

I am unable to use the 2-factor authentication method, so I downloaded the Xfinity Authenticator application.  In the setup of the application, I authenticate with userid/password, then I am presented with my mobile phone number and third party email address on the account recovery options page.   I select the "Looks Good" button.   Then I get an message "That phone number is already in use on another account".    Yes it is and it is in use for the account I am attempting to setup the authenticator.   I have not way to complete the setup.    This is the same stupid error with the 2-factor authenication problem.   I have multiple accounts with Comcast and have one mobile phone number.  The setup fails when attempting to setup recovery options - I should be able use a mobile phone number of my choice for recovery.   Please fix this problem.