Phone charges off of Xbox but Xbox itself won't turn on?

Why won't it turn on? Tried resetting it tried using controller to turn it on, tried changing outlets and power strips, left it unplugged for hours and tried again, nothing is working. It can't be the power supply if my phone charged when I plug it into the Xbox, right??? I was gifted a year long Xbox live membership from my husband for Christmas and I am super bummed that I can't activate it and enjoy it right now :(