Question about Sony Icd-Tx650

Hi, I managed to charge it once after discharging, then I used it again and discharged it and now it won't charge. It says "Battery low" every time I turn it on, and when I plug it in, a yellow light comes on and then goes off after a few seconds and it doesn't show any signs of life. Tried it with several different chargers, nothing. I've recorded lots of stuff on it, what's going on? Can you help me?