Upgrading account from free to business

Hi, I created a free account to take a look at the layout etc. I now want to upgrade to a Business Account, but the only option for a straightforward upgrade is to Premium. The Business option isn't there.
I'm unable to purchase Business from the main menu, as my email has already been used!

You need to login first and then visit the pricing page. Here you can choose your desired plan and follow the checkout process.