Clicking on BUY THIS COURSE take new user to checkout with no option to register

I have enabled “Enable Register Form” (Enable register from profile if the user is not logged in.) on the settings.

However, when you click on BUY THIS COURSE without being logged in, it directs you to the Checkout with no option to register. It also incorrectly says you are a “Returning Customer”.

Also how can I change it to say “Back to Course” instead of back to “class”.

Thank you!

The page I need help with: [log in to see the link]