I am applying to US universities for Ph.D. so I wrote to some professors from X university. Actually, I wrote them at the beginning of this year but I was late for admission so I did not get any positive reply. But wrote them again last month and one of them replied asking if I have time (that week) to discuss my further goals with her. I replied saying I got time. After that, she did not reply. So after 3 weeks, I sent her a reminder email. She did not reply. At the beginning of this month, she again replied and asked if I have time for an interview. Again I said yes and we fixed a time. On that day, she wrote me she got some work to be done and again if I have time in the later week. I said yes. Again she didn't reply back.
What should I do now?
If I can manage a PI before I apply to this university, I will have a good chance of admission and they will waive my application fee.