Why would we receive a message in iService that does not display anything for the message body? When we review the original message.eml attachment we can see the body.
Email messages are typically sent in "multi-part" format with separators in the message that split up the plain text and HTML versions of the message body. Within iService (Supervise and My Queue>Message Details), we display the plain text version of incoming email for a variety of reasons. One reason is that it is unsafe to load HTML directly in your browser from an unknown source.
If you view a message in Supervise or My Queue and the body appear blank, but you see a message body within the attached original email, then most likely the message was sent as HTML only. Most modern email clients (Outlook, Thunderbird, Gmail, etc.) will not allow you to send HTML only emails, so most often these are either SPAM or a poorly formatted message from a mail form or utility.
If these are sent from a utility or email form that you have setup, you need to update the form to either send plain text only or a true multi-part message.