Is it considered breaking an oath if a husband swore not to deal with a woman, and then his female boss at work contacted him to give him the schedule?

If the husband intended not to interact with any woman, whether by phone or otherwise, then he breaks his oath if that woman contacts him and he interacts with her regarding his work. However, if he intended that phone contact would not be included in his interaction with women, or he excluded the department head from the generality of his oath, or his intention was specific categories of women or a particular type of interaction, then he does not break his oath if his intention did not cover what occurred.

In the case of breaking the oath, if his oath was by one of the names of Allah Almighty or one of His attributes, then expiation for an oath is due upon him. If he swore by divorce, it is effective according to the majority of scholars, including the four madhhabs, while Sheikh al-Islam Ibn Taymiyyah holds that expiation for an oath is due upon him if he did not intend divorce.