Renunciation Application - Approved but package not sent out.

[saga]

I applied for Renunciation at the San Francisco mission through VFS. Sent in the application via USPS and enclosed a label and envelope to send the passport and certificate back. Yesterday i got an email/text saying that the renunciation is approved and will be sent back with the enclosed envelope.The tracking number on the return envelope is still shown as "not picked up" ("Pre-shipping"). I tried to schedule a pick up with USPS at the CAC San Francisco Centre: 642 Harrison Street, Suite 200, San Francisco 94107, CA. But USPS does not allow me to schedule a pickup as the address is not available for pickup. I am not sure what do to next. Anyone has any experience with using their own envelope?