Using the phone to call Kawakami is exclusively for her Confidant. If you want her to do laundry, what you want to do is head to the laundry place, put in whatever you want to clean, choose to run the wash and then you'll have the option to call her to take care of it for you. Keep in mind having her perform a task for you like this means you can't spend time with her towards her confidant link even if she was otherwise available that night. On the other hand, you can have her do these tasks for you any day not just those where she's available for her confidant.
Also, if the task you're calling her for is inside Leblanc, like making coffee (like with laundry you would interact with the coffee machine and if you try to make coffee you'll get the option to call her), Sojiro will leave and thus be unavailable as well.
Thanks, I should've tested these things out more thoroughly, I have a ton of grimey shirts and stuff. ---
Not changing this sig until I decide to change this sig. Started: July 6, 2005