I have 2 email addresses/logins via comcast.net but only one cell phone number. I associated my number with one of the emails but I can't set that same number for my second address. Since I only have one cell number, how do I assign a number to the second address and account?
It's a security thing. You can't reuse the same phone number within the same Comcast service address. However, you should be able to use an alternate email address from some other, non-Comcast, email provider instead.