Well if it is not turning on anymore, it could just be a dead battery. While it seems like you can't change one in a tablet, you actually can. It just takes a bit of effort.
First though, I would check to make sure there is nothing wrong with the charger cord. If you can, see if it works in a different device. If it does, then the problem is your device. If it doesn't, it might be just a simple cord replacement to fix the issue.
Should you choose to open the device, so you can change the battery, then there are tons of videos out there that can show you how. If you feel comfortable doing it yourself.