dying issue

My M6SP has begun to die rapidly. I will charge my m6 for sometime and disconnect when needed, So im listening to some music when i begin to notice that my players battery icon looks as if its charging moving from full to no battery charge constantly. I leave it alone and continue to listen to music moments later my M6 Auto shuts down due to low batt.
Please someone help I have tried reseting,reflashing, and formatting, no idea what to do next.

If you've used it regularly for several years, the battery may have died of age. They will only last so many recharge/discharge cycles.