The phrase "are at service" implies a willingness to assist or help others. Therefore, antonyms for this phrase would be words or phrases that indicate a lack of willingness or ability to help. Such words might include "unavailable," "unresponsive," "uncooperative," "ignoring," or "unhelpful." A person or organization that is not "at service" may be deemed unapproachable, indifferent, or even hostile. In contrast, those who are "at service" are often valued for their helpfulness, openness, and compassion. Therefore, choosing the right antonym for "at service" depends on the context in which it is used and the intention behind the message.