ELH's issue was due to a back-end system where his identity was tied to a legacy billing system account and happened out of nowhere. The fix was we invited his other mobile number to create an Xfinity ID (a secondary - manager), and used the "Transfer Admin Rights" to promote it to his primary, and we changed his username.
If you ever have issues with signing in, you can go to xfinity.com/password and it will text you a code to reset your password.
If for some reason you can’t sign in and pay, you can go to https://www.xfinity.com/bill-pay?pc=1
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