My son received the call back on the day following my call to them. However, he did miss one call because he fell asleep. We are still waiting for the 2nd. call which should be from the Dr. himself I understand. We were told that should be within three weeks. We are only in the 1st. week yet. Even so, I am in the process of getting birth certificates and passports seen to so we'll be ready whenever the call comes.
How long has it been since you received the initial call? And may I ask where you live? If it has been more that 3 weeks I suggest making another call leaving a message that you think you missed 2 calls due to time differences. It certainly can't hurt to do so.
Good luck and let me know if you find out anything. And from one newbie to another - WELCOME.

Guider