Sometimes an order can be split across different delivery methods (for example, your sanitaryware may be delivered via van, while your tiles may be delivered via a pallet courier due to their weight). If you received a delivery docket with your order, please check this to see if your missing item is listed. If it is not listed on this docket, this means it wasn't due to be delivered in this shipment and that it'll follow on a separate delivery soon.
If the missing item is listed on your delivery docket, please contact our Customer Support team who will investigate & resolve this for you.