Is it Haram to use the office's phone to talk with my family? (Shia & Sunni view)

I have heard that it is not permissible for the clerks to talk by the phones of their office(s) in personal fields (such as speaking to their families and other personal jobs). Since it is not a personal device. In truth, I wonder if it is a Haram act. (I’m looking for the viewpoint of the scholars (both Shia and Sunni scholars), because there was not any phone device at the time of the Prophet (SAWW), thus rationally there couldn’t be any related hadith regarding it)