The antonyms for the phrase "calls up on" are many, and they all denote a lack of need or urgency. The most common antonym is "ignores," which means to disregard or not pay attention to a request. Another antonym is "disregards," which means to pay no attention to something. Additionally, "neglects" is an antonym that means to fail to do something required or necessary. Other antonyms include "drops," which means to abandon or stop something, and "omits," which means to leave out. Ultimately, using antonyms for the phrase "calls up on" can help convey a lack of urgency or importance in a given situation.