Can't get past an authorization request for 1 song

I just purchased a song at the iTunes store and was told my computer wasn't authorized to play it. So I deauthorized all computers associated with my Apple ID and reauthorized my computer. But I still am not authorized to play the song - over and over and over I get the notice that this computer is not authorized to play the song. Restarted my computer and it made no difference. I purchased another song at the same time which I can happily play. Can someone please help me with this, or tell me how to get my money back from Apple?