Photoshop: Can't sign-in because of "no internet connection" warning

I can not open PS CC on my computer, after using it for about six months. I receive a sign-in required message. But the next screen reads "no internet connection". Of course I have a working internet connection. After a on-line chat support and several hours of tech. phone and computer linked support from at least three different "Peters", PS CC still will not open. They said call back tomorrow. These sessions with various Peters came with a $150.00 price tag. My case # is 0214114935.