Battery not charging

Make an appointment at your local apple store or authorized service provider and have them check it out

Have you tried to force the iPad to reboot? Hold down the sleep and home keys for 20 seconds or so. When you see the silver apple, let go and let it reboot and try again.

Also, do you have a cable and charger you can borrow? Or try yours on someone else's iPad just to rule out/in that they are fine.

I'm having a similar problem on my ipad air and mini. Tried multiple cords/wall warts/outlets, tried cleaning contacts, forced restarts and restoring from backups. No luck. They will charge despite saying they aren't, but it seems slooooow.