Block all senders except for Contacts
Avoid the frustration of unwanted emails by enabling the option to only receive messages from senders who are in your contact list. If you're expecting messages from a specific sender, be sure to add their email address to Contacts.
1. Under your Username, click Options | Mail Settings.
2. Click the Block Senders tab.
3. Select Only accept mail from people in your contacts.
4. Click Save Settings.