Yikes! That's a big difference. Probably not an Amazon funded sale. Make sure you don't have any coupons or promotions running that may have been applied to these items.

I would create a case with seller support and include screen shots showing your minimum pricing and order showing it sold for significantly less. But you probably won't get an answer back before you'd have to ship. I'd be inclined to cancel the orders and say there was a pricing error.

Please come back and tell us how this turns out.