From the Account Sign In page:

  1. Select the "Unlock Account" link located at the bottom of the page. 

Just like "Forgot Password," a user can request that their account be unlocked:

2. Simply enter your mobile device number, or your email that you used to register your account, and follow the directions. 

3. After you enter in your recovery information (email or mobile device number), you'll see the below message.

4. Follow the directions in the email or enter the text verification number to have your account unlocked.