INFOPASS一問，謝謝有類似經驗的朋友幫忙！

想安排一個預約去INFOPASS我的I485。可去了網站隻能選
Case Services follow-up appointment - If it has been over 45 days since you contacted NCSC and have not received a response to your inquiry. You must bring the Service Request ID Number related to your inquiry to the appointment.

請問從哪兒拿到the Service Request ID Number？難道一定要先打NCSC電話(請問誰有這電話號碼？請告知，謝謝！)然後才拿到這the Service Request ID Number。第一次申請，請有經驗的朋友幫忙！萬分感謝！！：)