Up until now, when a download was downloaded by a purchaser the seller was immediately paid. The buyer didn't have to mark the purchase as complete. We just updated this functionality, buyer's (or an admin) have to mark downloads as complete.
You are probably wondering why we are creating more busy work (and making it a little bit harder for sellers to get paid). The reason is, we realized that sellers could use the automatic nature of the payment to scam buyers. For example, I could say that I was selling you my awesome bands CD. You would think, "Great, just take my Ð, I wanna hear it!" Once you downloaded it though it turned out that I, being a bad shibe, had actually uploaded a text file that said "All your coins are belong to us" as the download. Unfortunately since you had downloaded it I would have already been paid and it would be an awkward situation all around.
Sellers, don't worry, you will get your coins, it just may take a little bit longer. Buyers, remember to mark purchases as complete.