IPhone won't download purchased song?

So I downloaded a song on my iPod. Then I tried to download the same song on my iPhone, but next to the song (where you would click to boy) says purchased and won't let me redownload it. I checked in my library, then under purchases and don't see it. How can I get it to download? I don't even care if I have to pay for it again, I just want the song on my iPhone.

Music -> purchases

if it still not there you must download it from iTunes and sync it to your device.simply login and at the top click Purchases.

heres a screenshot of where to go to download the song again for free:

You should do it manually from a computer, it will work for sure.