So here is where you have some decisions to make. Can you return or exchange it for a new device? If so, do that. If not, here are the first scenarios I see right off the top:
1. The battery is the issue. Without opening it up and seeing exactly what battery is there, you don't know what type you need, or if you can find a replacement.
2. The charger connection is the issue. Could be as simple as a loose wire. Open the tab, slap some solder on and away you go.
So, if you feel you can open the tablet without doing too much damage, and if you need to remove the battery or change wiring, then what have you got to lose.
On the other hand, maybe you are better off making this something like a dedicated tablet hard-wired to an outlet in the Kitchen or Bedroom and get yourself a new one.