Recently (~1 week) my emails from yahoo all disappeared and when I get new emails now they do not stay. There may be 30 new emails then if I go back to look again there are only like 3 emails. I have no clue what is going on... anybody have any suggestions?
Are you using the native email app that came with your phone or a stand alone app?
If the native one that came with the phone from verizon, just delete the account since its buggy and unreliable.
Go to the Google Play Store and get the YMail app. (Yahoo mail is now YMail)
you need only login with your yahoo user name and password and no special settings are necessary.
You access the app settings and select how to get your email, the tone to make when new mails arrive, as well as what folders to sync and how often.
This works much better I think you will like it.