How do I get a song from my iphone on to my computer?

I bought an album from itunes on my iphone, yet it won't appear on my itunes library on my computer. When I look at the album on the itunes store on my computer it comes up as purchased. When I go on to purchased songs on the itunes store on my computer, it doesn't come up either. However the album still appears on my phone and can be played normally. This has never happened to me before, as the songs usually appear on my computer straight away through icloud. Any help would be appreaciated.