Hi, I'm having problems downloading a song.

I downloaded the song but when I played it, the quality was exceptionally poor and it sounded like it was slightly cut (ie shorter than usual). I deleted the track from my computer then went to download the same song (from a different source) but I can't seem to download it again! I've practically tried every other source to download from but when i try the status bar says connecting... then after a while it says need more sources!

Is this something to do with having downloaded it previously?

Can anyone help?