To view your invoices simply login to your Stallion Hosting client area at: http://www.stallionhosting.com/support/clientarea.html
Your username is usually the email address you signed up with.
If you have forgotten your password then you can request a new password.
Once logged in click the My Invoices link and all your invoices will be presented, click on the View Invoice link to view them, there is also a link to download the invoice if you need to.