If it isn't charging, and you are sure that the charger cords you have tried are all good (they work with other devices) then your battery is probably needing to be replaced.
If the tablet is under warranty still, then I would contact the manufacturer about having it replaced (the battery). If it is no longer under warranty, then you have the option to try and do the replacement yourself (it can be done, it just isn't 'simple') or taking it to someone who can do the work for you.