Tbh I don't think that was a delivery. The setup, the look and style of the person outside the door, and the reactions all imply it was a circular notice, i.e. a neighbor dropping by with a "pass this on" message for the tenants.
@NinkNikkita According to another ghost manga I read, in Japan dolls become cursed when they are neglected. So hiding one in a bathroom cubbyhole is a good way to get an angry doll, while taking care of it and playing with it will placate the doll.