Here are two ways to create a CSV file on a Mac that can be input into the website:
1) From Email reader using TextEdit -
A) Open TextEdit and select Format->Make Plain Text
B) With the mouse select the text in your email and copy and paste the text into the TextEdit window
C) In TextEdit select File->Save As and at the bottom of the Save As screen select Unicode (UTF-8) as the Plain Text Encoding
2) Using Numbers -
A) Go to File->Export and select the CSV Tab
B) On the CSV tab select TextEncoding as Unicode (UTF-8)
C) Then click Next and Save