Modem setup

While trying to setup my new modem following the instructions. When I go to the app it hangs on finalizing. It sat there for over an hour. My problem is the cell service her is poor and causes many problems. Why I use wifi at home. With the modem disconnected I have little cell service if any for online apps. I need a phone number to speak with a person to get this modem setup. Do you have a phone number I can call instead of app?