It is important that you stay current on the email in your client area.
Your hosting company often will generate important email that you need to keep, so it is sent here so that you can easily retain a copy of it. This tutorial will assume that you are already logged in. If you are having problems doing that, or don't know how, please view the tutorial named "How to Login to the Client Area".
On the main client area menu, click on the 'Hello, [Username]' -> Email History link. This takes you to a page called My Emails, which is a complete history of all email messages you have been sent, and any you have sent to them. It includes invoices, order confirmations, supports tickets, payment confirmations, and more. Just click on the Message Subject to read the email.
Be sure to check this area often, so that you can see what emails are being sent to you through the billing system.