May 10: Sent I-751 package via USPS to Phoenix P.O. box
May 13: Package delivered
May 16: Credit card charged
May 21: Status changed to "Case Is Being Actively Reviewed By USCIS" / extension letter & biometrics letter available in online account
Sorry to start a new topic, but I've seen conflicting reports on this. Does anyone have a definitive answer? Does the receipt mailed when the case is received double as the extension letter? Or does that arrive separately at a later date?