This offer appears to be targeted to their email list, and meant for when using Visa Checkout, but the
terms and conditions, despite mentioning "Online Orders Only - does not apply to orders placed by phone", nevertheless says at the bottom of the page
"Prefer to order by phone?
Contact Shoebuy.com Customer Service toll-free at 1-888-200-8414 and mention the promotion "$50 off $100!" to receive your discount. From outside the U.S. call +1 617 451 2880." So if you call, you may be able to get it even if not targeted, and even if not using Visa Checkout.