pending download

I purchased a song from itunes on my laptop. I am able to listen to the song in itunes and on my iphone, but can not actually download it to my laptop. It shows as a pending download under my purchases. When I "check for available downloads" I get the message "no downloads available." I've logged out, restarted itunes, and logged back in. I restarted my computer. The purchase is already posted to my bank account and yet I can not download it. Any ideas?