when I read a phrase like "our international customers" they aren't specifically referring to people who have ordered in the past, they mean "any international person in a country that we service."

Well, first of all, I don't know how you get "our international customers" out of これまで海外発送をご利用いただいていたお客様. But more importantly, the other guy in the thread wrote and specifically asked them (because he also thought I was being too literal) and they confirmed it. New customers (or customers who have only placed domestic orders in the past) won't be able to ship internationally after the change.