My latest adventure with Kobo:
Apparently, when you buy an ebook that you once saved a preview of to your Kobo library and then subsequently deleted, you get to enjoy the experience of your newly purchased ebook going directly to your "Trash" (they seem to like to update your previews with the "real deal" if/when you purchase them). At which point you can undelete your brand-new purchase.
At least that's how I'm explaining the fact that a book I purchased today turned up in the "trash" with a deletion date of nearly a year ago.
So remember to check your trash if your new purchase isn't showing up in your Kobo library boys and girls.