The expectation for a 4 yea old to stop playing on a playground is a little too old for 4 . A teen should be able to that. 4 year olds barely grasp the concept of the phone. Stopping to play to talk through this thing where I just hear a voice I feel isn't reasonable to force. Pick up your toys when you are done playing? On their level of listening and obeying. A concept they can grasp.
I've been doing this raising a kid thing through divorce since 6 months old. Often my daughter never wanted to talk on the phone to either of us. I asked my IC about it. She said it isn't reasonable to expect a child of that age to want to talk on the phone because it is not visual and cannot grasp their attention. They don't quite understand it. So neither of forced her to talk to us. Once in a while she would say "hi" then get distracted by something visual or tactile.
