Sometimes the spam filters used by ISP can delete mails you’ve actually requested to receive.
so you never get to see/read it!

(A) For Yahoo! users:
1. Open your Yahoo! e-mail account
2. Click “Options”
3. Click “Filters”
4. Click “Add”
5. Click in the text box in the top row (”From header”) and enter xxxxx.com
6. In the pull-down menu for “Move the message to”, choose “Inbox”
(B) For other email services:
Add xxx.com to your address book or list of contacts