Normally, after 2 or 3 time without a proper answer, they should be striked (not fired, its before fired). Else, people can't legitimate hierarchy status. After all, its a professionnal place, feelings can't overwhelm that hard a job, without at last communication to explain why its not going right. Its most important to find solution. Its not to be naive, or emotionnal. If job cannot be done, job cannot be guarantee.