Could it be one of these ?     

  •  Have you already applied a promotional or discount code your order  - we do have a limit of one code per order.
  • Your code is for a free item - Please make sure you've added the product to your cart first unless the offer specifies otherwise. (this one gets most people, it's not just you!)
  • Are you ordering an automatic delivery? Unfortunately free product discount codes don't work very well with our automatic delivery software so please just go ahead and place your order then email us immediately after and let us know your discount code and which product you'd like added to your order. 

Please note; If this doesn't answer your question, it is important that you email us right away to make sure we don't ship your order without sorting you out! Thank you very muchly!