Sephora Failed Order, Invalid Code

I placed an order (Order No: 8000500626) on October 29, 2022, from Sephora for a rare beauty blush that was not provided to me. The customer representative offered a 20% discount as compensation. However, when I revisited the payment screen today, they claimed the code had been used and didn't activate. It's frustrating how I always encounter issues on the Sephora app whenever I shop. The rare beauty blush is rarely in stock, and with the inflated prices, I wanted to purchase it while it was available, but I couldn't due to the discount not being applied. I demand a response to resolve my dissatisfaction and the renewal of the unusable code. Otherwise, I will share my complaint on various social media channels and, if necessary, file a complaint with the Consumer Arbitration Board regarding the failure to deliver the purchased product.