This would be the first time I ever heard a complaint or issue with overcharging. I have my doubts about that being the problem. Can you get it to work at all? It sounds more like a dead battery or a bad charger.
The immediate shut downs are because the battery doesn't have enough energy, rather than having too much. Lithium batteries have internal circuitry designed to prevent overcharging. If this circuitry failed the results would be quite explosive, so it definitely isn't an overcharged battery.
Assuming this tablet charges through the USB port, plug the tablet into the USB port on your PC while the computer is running and leave it for several hours. Disconnect and try powering the tablet up. If you get it to stay on more than a few seconds your charger has gone bad. Otherwise it's the battery.