There are 2 possible reasons:
There has been a preparation error.
Some of the products ordered have been received, but one or more are missing?
This is due to a preparation error on our part. It's very rare, but it can happen, and we apologize for the inconvenience. Customer Service will be happy to suggest a solution.
We invite you to click on this link: Contact Customer Service.
The product was no longer in stock.
Just as rarely, it may happen that a product that was in your shopping basket was no longer in stock when you placed your order.
When this happens, you are immediately notified at the top of the payment page, which shows the final contents of your basket. So you can place your order with full knowledge of the facts.