The final sale has not ended. Apologies: that has been occurring on certain browsers and has wreaked a bit of havoc on our back-end. It's a development issue, and our web guys are on it.
What we've been telling customers is to go ahead with the order and then send an e-mail to customercare[at]carsonstreetclothiers[dot]com explaining the issue. Our Client Relations Manager, CB, will process your order for the correct discounted amount.
Sorry for such an inconvenience. Also, you could always call the shop and place the order by phone, old school style.