Isn't that the support haven't understand that you want is just make themselves change the information? Maybe they answer that way to you, thinking you want be able to change that data yourself. That is reasonable, sure, bus as long as site won't allows it, yet cannot be done.
Try contact support again and ask them "Hello, I moved cron Canada to US, please can you update my country and region accordly, as long as I cannot do that myself ?"