Hello cropsprayer,
Thanks for reaching out to us in Apple Support Communities about not being able to completley download mail. We're happy to help by looking into this more!
The following support article provides some troubleshooting steps to try for this behavior: If you can't receive email on your iPhone, iPad, or iPod touch - Apple Support
Try all the suggested steps in the article, but the last may actually be the most helpful:
Remove your email account and set it up again
1. On your computer, sign in to your email provider’s website. Make sure that all of your email is there or make sure that your email is saved somewhere other than your device.
2. On your device, go to Settings > Mail, then tap Accounts.
3. Tap the email account that you want to remove.
4. Tap Delete Account.
5. Add your account again.
If these steps don't work, contact your email service provider for more information.
Hope this helps.
Best Regards.