Sofortüberweisung, left payment window and now can't finish transaction?

[kratosthehamster]

I wanted to buy a game over Sofortüberweisung, since I am German and in Germany. When I was about to enter the credentials into the SÜ-window, I got a little paranoid and needed to check if that game was really playable on my OS and accidentally left that window. Now Steam wont let me back to pay. When I try to check it out again Steam tells me I would purchase it twice, because the pending transaction is still open. Well great, but I can't access it anywhere... Any ideas?