Why is my chromebook dead after plugging in an iPhone to the USB port

Hey guys

My chromebook (Asus C300m) was working perfectly until I plugged in an iphone into the USB port on the right hand side.

There was a click sound, and then the device went dark. No screen power, LEDs or sounds. Device doesn't power up.

I've tried to plug it in, recharge it, and every thing I can think of but the device is dead.

I've followed the troubleshooting steps on iFixit. But nothing works.

What should I do next?