Completely no reponse/won't charge

i bought Sansa clip+ for about less than a month. I played it everyday, and really enjoyed it. yet today, while i was listening to the radio, it stopped working. i thought it was low battery. but when i plugged it to charge, it didn’t respond at all. the screen just stayed black. pressing any button wouldn’t work either. does anyone know what is going with it? many thanks

thanks a lot. it works!