I'm sorry you're having such problems with your Wii U console, but have you tried fully disconnecting the AC Adapter from both the electrical outlet and also the console too?
If you do unplug it for at least a couple of minutes, that will reset it and may allow the console to power up again.
But if it still no luck, then give a call to Nintendo's 1-800-255-3700 (6 am ~ 7 pm Pacific, everyday) Customer Service number, or use their webform to contact them, and one of the service representatives can discuss repair options with you, sorry.
But at least the slightly good news is that this repair should be covered by the warranty and also won't cost you anything to ship it to them.