After logging into your online portal, click on the My Conferences tab.

Scroll down to find the meeting you need a receipt/confirmation letter for.

You will see an icon to the right of the meeting title that is a piece of paper with a $ sign. Click on this to download a PDF of your confirmation letter, which includes any payments made.

Alternatively, if you click on the meeting title, you can click on Download Confirmation Letter under where the Tuition Fee is listed.