Can a phone without credit call someone?

So basically, my friend and I had a fight and she doesn't want to talk to me. And then she went shopping and she wanted to get something but she didn't know where to get it. She called her dad at home and ask him to call me and tell me to ring her. I then ask her if she ran out of credit and she said she did. But I don't get how can she call her dad and ask him to tell me to ring her, but can't ring me herself?