I changed the translation of "Wie bitte?" to "Come again?". "What was that?" would probably also be appropriate but is even more informal. Either way, in almost any instance I experience it being used, it's used to prompt the speaker to repeat or clarify something that was just said. In this case I think "pardon?", while polite, by itself just doesn't quite convey that meaning as well as it should, and so I've changed it.