Yahoo Iphone Mail App Issues

I'd like to temporarily retain my Yahoo Mail as I switch to The Apple Ecosphere...

After downloading The Yahoo Mail App from The App Store, and setting up my accounts, multiple links to the two appeared in my accounts' list, @yahoo.com and @att.net (both run by Yahoo but inexplicably still having two initial login links mail.yahoo.com and att.yahoo.com).

Inorder to resolve the two accounts failing to properly 'synch' in the new app (thus creating the duplication error) I need a fresh download. But the only option offered in The App Store to reinstall it is 'the cloud icon', which retains the information I need to freshly reenter, which cannot be resolved within the app by either 'managing the accounts' or 'deleting the mailboxes' features (without deleting everything).