I received NOA on 9/15 as well.
Still no news about either biometrics appointment or reuse of it.
For the service inquiry (Non-Delivery of Notice) that I made last month, I've got some answer from USCIS (it took a little less than 2 weeks), however their reply was not that helpful.
This is what USCIS said on the email :
"We have received your service request and researched the status of your case. You indicated that you have not received a notice for your biometrics appointment. We have requested that you be scheduled for a biometrics appointment. You will receive an appointment notice as soon as there is an available date and time at your local Application Support Center (ASC). Due to backlogs at some sites it may take more than 90 days for this appointment to be scheduled. "
Call USCIS OR ask Emma if they received your package, and ask if your receipt number can be shared with you.
I remember someone got his receipt number through Emma chat; the agent would ask your name, DoB, etc.