They probably refund some portions to maintain the image of good company. Besides those who paid with services like earlier mentioned PayPal, got some buyer protection as well to force them to get theirs money back.
I wonder how many people paid with BTC... ?
Good point. Something to consider is that by offering refunds back, they know only a small selection of people would request one. Hearing about the refunds makes everyone more at ease, meaning new people are making purchases. It is a smart thing to do if you want to scam even more people.
This isn't to say that they are scamming. I haven't gotten involved with them so I don't have personal experience with them. Just saying that refunds aren't necessarily a sign that they are legitimate.