If you've tried other cords as well as tried holding down the power button for a minute and trying to restart your problem is most likely your micro usb port/pwr jack.
It has separated from the board and needs to be re-soldered and made sturdy again.
If you are great with a soldering iron you can do the repair after watching a few youtube videos but it is a tight and tiny repair.
If not I strongly recommend sending it to us. We are fast, thorough, very familiar and make the port more sturdy than factory original.