Actually if you try calling you will often get a recorded greeting or voicemail, especially if it's a peak time
So no need to call
Just go to her address and ring the bell. That's what she wants: walk-in cash, no effort and no selling required on her part.
Now, after the session, she might well offer you her real number ... the cell that she actually takes calls on ... that can be useful if you wan to confirm she's free.