Who is it?...Can I say hi?...I want to say hi!

I spend more time on our family home phone than anyone else does. This is because it's my primary business line for Tupperware. Lately, whenever the phone rings both my kids are in my face asking if it's their daddy. If I shake my head no or tell them it's not him before I answer it, they will usually walk away. However, Isabelle, lately has been continuing to ask who it is, unless I stop and tell her. Then she insists that she wants to say hello. If I say no, she will instantly throw a fit. It was cute at first (not the fit), but my last couple calls have been customers and I have to excuse her rude behavior as I am trying to have a business conversation. I've even ran and hid in the bathroom just so I can have a conversation. For the most part people are very forgiving and understanding, but I get so angry because I think it's very unprofessional. I have been trying to talk to Isabelle about not continuing this behavior, but it does continue.