i am following the initial first steps upon opening the shopify free trial. i have followed the first two steps, add your first product, and choose a theme, flawlessly. the third step is to purchase a domain. i get an error message that says to purchase domain you must upload a valid payment method, with a link that says billing settings. i have already entered my credit card information, and when i click on the link it takes me to a page that says "add address" "you have already added an address". this page does not appear to be the billing settings page, because if i click to a different setting and then back to the billing settings tab, the add an address prompt is gone and my credit card information that has already been entered shows up. i try to purchase the domain again, and get the same error messgae, get sent back to the add an address page, even though ive already entered address and credit card information. my first hour using shopify has been going in circles and troubleshooting experiencing this obvious glitch. please help.