Access denied trying to log into Xfinity app

Both my husband are not able to access app on our iPhones.  Been customers for years.  Spoke to Xfinity customer service, they had me do all these steps but I still get "access denied"  I have tried using my wifi, cellular service, and other wifi.  We still are not able to get into app.  I was told yesterday I had to go into store. But not sure why I need to do that. HELP!!!