My tablet wont charge and it wont hold a charge

My RCA tablet wont charge, and it dose not hold a charge anymore. The battery would charge then stop charging when it was a little past 50%, then it would stop charging and start de-charging. It continued this cycle for about a week, and my tablet has be plugged in ever since. I have tried to switch the tablet on, but it would not work.

The model for my tablet is RCT6973W43.