Q: Incomplete downloading of iTunes song even when says is complete

I used iCloud to download a song onto my computer that I had purchased on my phone.  I says it the song is 2:54 long yet at about 1:15 the song spontaneously ends and goes to the next track.  I do not have this problem with the track on my phone.  I wanted to re-download it however when I deleted it from iTunes on my computer, when I went to the iTunes store it still said that track was "downloaded" to this computer so it wouldn't let me get it again.  Thoughts?