Payed full price for a Blue Dot Sale item

I'm rather disappointed and annoyed with the experience that I had with the last purchase I made at Takealot. I had an item in my cart that was marked down due to the blue dot sale. The sale expired 28/11/2021. When I made the payment, on the evening of the 28th, I noticed that I got charged the full amount and wasn't given the promotional price. I took it up with customer service and was told that the sale had ended and they are sorry for any inconvenience caused. I made the payment on the last day of the sale so therefore I should've still received the item at the promotion price.