Device will not hold a charge.

Device will not hold a charge.

Hi there! It's me again! So found a new problem. The device battery is not holding a charge. I will leave it on the charger to charge for hours so by the time I need to use it will be fully charged. Then when I try to use it, the battery level is already drained within 10-20 min. What could I do to resolve the problem or fix it all together?