On my Samsung S5 how do i get my emails to stay in my in box until i delete them i set up my email on my samsung s5 and i get emails but they disappear after about 15 minutes and there not in my in box, junk, or trash bins. In my settings i have delete emails from server set at never. how do i get the emails to stay in my inbox until i delete them?
Make sure your Email account is set up as IMAP (not POP3). 

In theory POP3 downloads a single copy of the email to the device that requests it. In practive, i've noticed the same issue you described whereby Emails seem to disappear.

IMAP syncs a copy of the Email from the server to your device to ensure you can view the same mail on multiple devices.