If someone is estranged from their alleged family, would you give that person the cell # to those family mem?

My dad raised a girl from the time that she was an infant until she was about 14. He has no blood relation with her. He cut her loose for his own reasons and hasn't spoken to her in 15 years. I randomly received a call from that girl on my cell and she addressed me as "hi sister". She has no relationship with me whatsoever. The only thing she could have been calling me for was to beg for money or something but all she got was the dialtone. I can't believe that someone gave out my cell number