The fare class hasn't changed, but your status has. If you don't have status, you can't select an E+ seat w/o a fee showing up. If you selected E+ seats free when you had status, those specific seat(s) should "stick" unless there's a a/c substitution - then all bets are off. Don't complain about not being able to change E+ seats. Be grateful you still have them - if UA was really mean, they could have sent you backward in the plane the moment status lapsed