Can't Delete Mailbox in iOS Mail App

One of the folders from my work exchange account has somehow been created into a Mailbox in the iOS Mail app. I've tried clicking on Edit then selecting that mailbox to delete it, but it's greyed out and all I can do is move where it shows up in the list of other Mailboxes. This is the 2nd time this has happened but the other folder was in my deleted items, and after permanently deleting that folder in Outlook it removed the mailbox in my iOS Mail app. As a savvy tech user, I most certainly didn't create that mailbox and it's really frustrating that I can't delete it.