You can view your invoice on your AddEvent account page after signing in. These are the steps to how you can check your invoices.
Click the drop-down menu on the top right corner of your page and click Account.

Scroll down to the Payment history section that you can find at the bottom part of the page.

If you would like your invoices emailed to you in the future, you can scroll up to the ‘Account information’ section (still on your ‘Account’ page) and enter your email address into the box containing the words ‘Email receipts to:’.