In the new email format, there are no schedules you can edit. Emails should be kept indefinitely until you delete them. Do you have the account enabled on another pc or mobile device using POP3? If so it may be downloading them and then deleting them from the server. How are you accessing your email-----with only a browser and the webmail UI or what?
I am using a POP3 that automatically goes to mail messages on phone and iPad. I believe once read they are automatically deleted. I would liek to keep them until I decide to delete them. Any suggestions?
Then your best bet is to enable the account on the phone and the iPad using the default IMAP protocol, then delete the POP3 version. With IMAP everything is synced so that anything you do to a message on one is reflected on all devices. Let iOS auto-configure the account for you and it will create it using IMAP. But then remember to delete the POP3 version or it will keep deleting the messages.