Issues with a secondary user trying to begin their own service at a new address

I have a family member who would like to setup their own service at their own address.  In the past they had used an xfinifty email address associated with my account.  We are having issues setting up their account and I suspect it's because somehow their phone number is still associated with my account.  I do not see them listed as a secondary user on my account so I cannot remove them.  I tried using the online chat to get this resolved, but after talking with two different people, I believe the problem is worse.  When I login to my account and click "Account and Identity", it keeps giving me an error and I can't see anything anymore.  I am not sure how to move forward and I would just like some assistance in confirming that their phone number and xfinity email address is no longer associated with my account.  Thanks