Dell UK 5% discount not applied

When I was purchasing a Dell laptop, I subscribed in the belief that I was going to receive a 5% discount on my purchase. Having made the purchase, I checked the invoice and found that the 5% discount had not been applied. The next day I received an email containing the code I would have needed to get the discount. I was not told I would need, or heave to wait for a code. I have taken advice which states "Pricing claims, including discount claims, must be clear and fair, and must not mislead consumers. I am therefore making a formal request for Dell to honor their discount before I take further action.

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