No button on registration page

Our registration page (www.xpansion.co/subscribe) is missing the button on the screen that is displayed after you've selected a membership and entered your username, password, etc.

The page says: "Sign up for Xpansion.co monthly subscription
Please check the details of your subscription below and click on the relevant button to complete the subscription." This is followed by a table with the following: "Xpansion.co monthly subscription R199.00 per month" and then there's a blank cell where I assume the button to proceed should be.

I have set up a payment gateway (2checkout) and am not logged in when trying to sign up, so I have no idea why no button is displayed.

I'd really appreciate some help getting this resolved. Thanks!