Hi Kristen,
Can you send an email to support at wordfence.com with your Wordfence username or email so I can find your account and determine why you can't log in (ignore the auto-reply you will receive). Also please include the phone number that is not receiving the texts in the email. If you need to get immediate access to your site here are instructions:
To get access to your site immediately, you can remove the Wordfence plugin. You can do this by logging into your WordPress cPanel and deleting the Wordfence directory usually found in a directory similar to public_html/wp-content/plugins/wordfence.
Once you delete the directory, you will be able to log into your site again. At this point, you can reinstall Wordfence from the WordPress repository (http://wordpress.org/plugins/wordfence/) and under the Wordfence Cellphone Sign-in page, delete the user that is unable to receive the text messages.
Once I receive the phone number, I will investigate why the messages are not being received.