<human>: Can you condense the text into a few key points?

I got a phone call from someone claiming to be my ex. She asked for me by name and when I asked who it was she would not answer, she just kept asking if this was <my name>. I hung up and she called back and left a message.... crying. I have an idea of who it is, but have not talked to this person in over 4 years. I want to do a reverse lookup but don't have the extra funds for the fees. Does anyone know a free way to obtain phone number owner info.  Some sites say it's a land line, others say cell.
<bot>: I am freaked out this chick may have a baby she wants to claim is mine and would like to get some background info before I answer... I don't know her last name...