Dependent cases will be

reviewed only after (or at the same time when) the primary (principal) case is reviewed. In your case, you never have such primary case which is supposed to trigger your case logically. Just contact INS to make sure your case is independent (primary) in their database record not dependent on other no-existing cases. Otherwise you could wait forever to have your case reviewed by a techcality. Do it make sense? So better call INS to clarify the situation and tell your concern on the type of your case.