We will ship all items from an order together in one shipment (although there can be multiple boxes within a shipment for large orders). If we ended up being out of stock of an item, your order will ship with what's available and we'll cancel off the out of stock item.
Please check your shipment confirmation email or the packing slip inside the package to see if the item is listed as part of your shipment. If it's not listed, it means the item was cancelled off your order and you will not be charged for the item.
If the item is listed on the shipment notification email and packing slip, there could have been a warehouse error for it not being included. Please contact customer service and we can help resolve the issue for you.