Email using too much memory

I had this same problem and spent a ton of time with online apple chat and many other sources, but I finally figured it out! Go to your settings, scroll down and click on "Mail". Delete all email accounts you have. Push the home button until you are on your home screen. Click on settings again, and then click on "iCloud" and scroll to the bottom and select "Sign Out". Push the home button until you are back on your home screen. Finally, delete the mail app, I mean the actual icon. You do this by holding your finger on the mail icon for a few seconds. When you remove your finger you will see an x in the left hand corner. Click this x. Your phone will ask you if you are sure you want to do this as it will delete all data stored on the app. Select "remove". Then restart your phone. When you turn your phone back on you will see your mail is no longer taking up any data. Now go to the app store and reinstall your mail app. Just type in "mail" and it will be the second option. Then you can click on this app icon and it will prompt you to log into your email accounts. You can choose to sign in to your iCloud this way, or from the settings menu. If you would like to sign into iCloud from settings simply clock on "iCloud" again. You will be prompted to sign in to your iCloud account and set your settings. If you need to add more than one email account, go to settings and click on "mail". Then click on "accounts". Next click on "add account" and proceed from there.

It seriously took me months to figure this out, so I really hope this helps somebody!!