After 4 long hours, and many people on the t-mobil team, I finally got my SIM card activated.
I'm sharing so you don't have to go through it, too.
I signed up and bought my SIM card through t-Mobil. That is the only service I have with them. Which ended up being the issue!
In order for the SIM card to be activated, it has to receive a text with the pin number. We had to pull out the SIM card from our "UNLOCKED" cell phone, put in the t-mobil SIM card, and continued with the sign up for the t-mobil touch ID to get the pin code. Once you have the pin code it is activated. Remove and put in the camera, and it works!
What a PITA!
Hope this helps someone.