This app allows you to control your Xfinity box through your smartphone.
You should know that this is not the official Xfinity box app, but this remote control app allows you to control it.

There are many remote models available in our app, so you can find one that works with your device.

The app will help you to use your Xfinity box even if you can't find your remote control. However, note that the app requires your phone to have an IR sensor.