shotty wifi service

I am having frequent issues with my WI-FI box for home internet. I worked diligently to find the best location in the house for it.  My TV will frequently go off line. My computer doesn’t stay connected. I can’t make calls inside my house when I’m connected to the WiFi.  I have to frequently reboot the internet box to gain connection. My internet app will show that all devices are connected, but they will not work. Is there anything they can do to make this better?