Use the Facebook Messenger Bulksender plugin with Facebook Messenger for WordPress to increase your audience for sending bulk messages. Moreover, you can use the Facebook Messenger answering machine to encourage users to post comments on messages on your Facebook page, automatically reply under the comment, and send incoming messages to those who commented. Facebook Messenger Bulksender is the best choice for free messaging, forget about MailChimp subscription.
Facebook Messenger Bulksender v2.0.1 – Facebook Newsletter for WordPress