@islands1213,
If you are pretty sure that you have gone through the entire setup process and connected the device to your network, this may just be an app issue - I would first try reinstalling the Kasa app to see if there were cached settings preventing the device from appearing.
The bottom right button on the HS220 is also a restart button, so you may try pressing that to see if the device simply needed another reboot to finalize its connection.
Otherwise, I would recommend checking to see if the device can be seen when connected to your wi-fi network compared to your mobile connection. If you cant see the device on either, I would try looking at the list of devices on your router to verify that you can see the device is connected to the network.
Also, what is the color of the lights on the switch itself?