My daughter is being harassed by another teenage girl, who says she wants to beat her up because she went out with her friend. This girl has my daughter's phone number and repeatedly calls her at all hours of the night from a private number calling her names and threatening her. If she does not answer the phone, the girl leaves her nasty voicemails. This has come to the point where she claims that she will come to her school to beat her up, even though she does not attend the same school. What should I do?