The guys above gave really good advise, but here's another tip:
ALWAYS check the return policy before you buy something that you have to try on.
Check zappos.com. They have a load of snowboard boots in all sizes. They also have a one year return policy and will pay for both the shipping and return shipping costs, so you can buy as many boots is as many sizes as you want and then just keep the pair that fits the best and return the rest.
Good luck with your situation, hopefully you can get it sorted.