Need to change email address for our account

I was signing up and paying for your service for my client and when I did, it connected me to an account for an old employee who is no longer with the company. Now I’ve paid for a year of service and apparently cannot use it since no one knows her login for your service and the email address no longer exists.

How can I switch this over to my email address?

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