Home line (No Line) error

Hello, I've been having an issue for the past 2 days. My phone has been displaying the text stating (No Line) and won't change. I've tried changing the phone and it's base, disconnecting it and reconnecting and nothing has helped. The issue occurred randomly after someone came to my house to install fios internet for the residents living upstairs, not sure if that helps figure out whats wrong, thank you for your time.