This would certainly be the most innocent explanation.  However, for a service that promised BTC in a few hours, I'm not sure why they would ever sell more BTC than they had on hand plus the amount that they could buy in realtime to settle the transaction.  Surely one of the key design aspects of a system like this would be to make sure that under no circumstances were they taking on trading risk for even a single transaction.  They are a processing company, not an arbitrage company.  I can't imagine that they wouldn't have it programmed so that it automatically stopped taking orders for BTC the moment that they crossed into this territory.

So for those reasons, I still think there is a lot more to the story (the simple fact that they have been lying and have left us to speculate, points to much deeper issues as well).