Van Ru, help please?

One of my student loans was placed with this collection agency less than 30 days ago. They have been calling my home during the day and leaving messages with my babysitter. TODAY, they called my Grandmother at 9am and told her I used her as a reference (not true.) My grandmother thought it was someone about a job, but was still upset and called me.

I called back and a nasty lady named Felicia is handling my accounts. I told her that she may contact me at this number and this number only. I told her I want her to stop contacting my grandmother immediately.

She told me that she won't contact my grandmother, but that if she calls one day and can't get a hold of me, that she will call my other family, friends, and neighbors until she finds me. This lady was rude to the extreme.

Can she call whoever she wants, even after I told her that I may only be contacted as this number?

She is collecting for a private student loan, not federal.