Are you sure that the battery is dead? It could be only deeply discharged, it could also be some other problem. If it is deeply discharged then usually keeping it plugged in for few hours will resolve it.
Not accepting any charge in case of a bad battery also sounds not very probable for me. In most cases one notices capacity loss first, and it is not that old, yet. I also have noticed some (rare, have not seen this for a long time) times the Gemini not charging despite of being plugged in. I would try anything else first. Replugging many times, rebooting, deleting cache (if on Android), etc. ..., before ordering a new battery.
Battery voltage might be below the charging circuits lower limit. Are you capable of measuring the battery voltage at the battery terminals?
Btw. are you using the original charger? I have noticed with a Samsung tablet, that it won't start charging with my 3rd party charger when it is completely empty. With the original one then it worked.