The pricing on the page comes with a reminder that promotional pricing is set at checkout and can change.
It means the figures on the page, however carefully shown, are not a contract. The price you are charged is the one on the checkout page at the time of your order.
It is a sensible caution and a reason for us to avoid hard promises about prices here.
Check the pack, the price per bottle, the shipping line and the order total before entering payment details. Take a screenshot of the final screen and keep the confirmation email. If the total differs from what you saw on the page, ask why before paying, not after.