Not Being helped by ANYONE in Xfinity

I need to talk to an agent to fix mty account because everytime I log in, and then try to do something (i.e., reset my new router, change my plan, etc.) it always says I don't have my "credentials" or on the app it says youre signed in but we can't access your details at this time. 

How am I supposed to get my internet connected. That being said, I have made multiple phone calls to try and get a hold of someone to help me, and over the course of two weeks, have had no help at all. 

Considering changing internet providers because this service is awful and unsupportive.