May I call the Phone company to install a phone line on Tisha Bav? Does it make a difference before and after Chatzos? Also, it is in Israel, where presumably the workers are Jewish.
Unless it is urgent, it should wait until after Tisha B’av, because we don’t want to be involved in anything that will take away from our thinking about the churban. Additionally there is no bracha in work done on Tisha B’av, although it can be argued that your not the one actually doing the work, nevertheless it should be avoided. It wouldn’t matter whether it is a Jew or a non Jew.
Shulchan Aruch 554-22, M:B 43.