Downloaded Apps on Nokia 5800?

I'm really confused because I downloaded an app that I really wanted then think I may have deleted it by mistake. Anyway now it won't let me download it again (presumably because it thinks I already have it?) so I checked my settings and it's definitely not saved anywhere on the phone/memory card. Because it still wouldn't let me download it, I formatted the memory card (presuming this would erase all trace of the app and let me start from scratch) however it's still not letting me get this and I don't know how/why and what I can do now to be able to download it again. It's a free app from the Ovi store if that helps explain things? Thanks in advance for any light you can shed on this!!