If it is because of Microsoft Exchange there is a simple solution.
I got an email from Rackspace the other day, and they have discovered the reason the Samsung phones eat up so much data with Exchange - the built in email app is constantly pinging the servers, resulting in the absurd amount of data used. The solution to this is to use the Microsoft Outlook app from the Play store. Please do the following on all Samsung phones (This does not apply to the iPhones):
1. Delete the email account from the phone.
2. If the Email widget is on one of the screens, delete the widget.
3. Download the Microsoft Outlook app from the Play Store (not the OWA app).
4. Open the app and re-setup the email using the Exchange protocol.
5. Enter email address, click Advanced Option at the bottom of the screen and enter the server info (connect.emailsrvr.com), username (email address), and password.
6. Add the Outlook widget (not the Email widget) back to the screen the email widget was previously on.