Flickering Screen and Battery Drain

Digiland Tablet DL1168A doesn't hold a Charge. At full battery the screen flickers and then stops when I plug it in. I suspect the battery but do not know how to go about replacing it. I called the 866 number but the voicemail is FULL so I couldn't leave a message and there was no other answer. How do I fix this?

Please contact me at barrett83801@roadrunner.com

Thank You,

Amber Barrett