Hi Limei - I just forwarded the latest email from Steve to you. Did you receive it? If you haven't already, please take a look at your Spam/Junk folders. Sometimes we caught in them.
If you still didn't get his message, here's an alternative way to get your code:
Please login to your domain manager under Store > Domains in your WordPress.com dashboard. There is help on how to do this on this page:
Once logged in, click on Tools > Exportable lists. In there is a file which has “Auth Code” under the Description. This contains the Auth Code (EPP) and can be opened in a text editor or spreadsheet application capable of opening .csv (Comma Separated Values) files.
I hope this helps! If you have any questions, just let me know :)