Missil GL-1502 mp3 player

I just got a Missil GL-1502 mp3 player, but it doesn't want to stay charged for any long periods of time. I can plug it in and charge it overnight, but it still only lasts for 3-4 hours before it drains the battery again.

Also, the jack for my headphones is all wonky too, causing the audio to cut in and out, sound like it's coming from down a tunnel, or only coming through one earphone. Originally I thought that my earphones had crapped out on me, and went and bought a new set. However, this did not fix my problem at all.

Are these common glitches that occur in my particular device, or did I just end up with one that's faulty?