There are 2 possibilities which could have resulted in the promotional price not being applied to your order:
- either the limited quantity of your specific size was already sold out
- you did not proceed to checkout in the allotted amount of time.
Please see below the specific Amazon terms, conditions and restrictions for Lightning Deals :
Lightning Deal Terms & Conditions
- Offer good while supplies last. A limited quantity of Lightning Deal promotional discounts are available per item. If supplies are still available after all of the Lightning Deal promotional discounts have been used, customers may purchase the item at its regular Amazon price.
- Each Lightning Deal is subject to two time restrictions. The first restriction is for the overall Lightning Deal and is displayed on the specific Lightning Deal. The item must be added to the Shopping Cart before time expires to be eligible for the promotional discount. The second restriction applies after a Lightning Deal item has been placed in the Shopping Cart and expires after a very limited time as indicated when adding the deal to cart. Orders must be placed before expiration to receive the promotional discount