If you see this message, there are a few things that might have happened.
Could you be applying a gift voucher code to this box ? There is a separate box for you to enter a voucher in - you may need to scroll down to see it, depending on what device you're using.
Could you have entered the code slightly incorrectly? Zeros and letter O can look similar, as can the number 5 and letter S. Any additional spaces may prevent the code from working, so please double-check.
Is the code from an old email or magazine? if so, it may well be out of date.
But sometimes we do get it wrong. If you are sure everything is correct, then please email us on cs@yougarden.com and we will check it out for you.