Why am I not getting any emails
None of my old or new emails are showing it says there is none but I knoowww there is
Device or computer?
For a computer - try rebuilding the mailbox by selecting it and then going to Mail/Mailbox/Rebuild.
If that doesn't work, try re-indexing the mailboxes. This can take awhile if you have a lot of mail.
Reindex messages For El Capitan, try looking in V3. Sierra use V4. High Sierra use V5.
Reindex messages (2) See post by Linc Davis
IOS
Have you tried deleting the account(s), restarting the device, and then adding the account(s) back?