I signed up for emails/texts, but they never sent me anything. I received a paper acknowledgement with the receipt numbers after 10 days or so from the time that FedEx delivered to the lockbox. Sometimes even if you sign up for them they just don't do it. You can try to call USCIS (to the automated person say "missing receipt number") and ask them if you can get the receipt numbers. My husband had to be on the phone for them to provide me with any information. We also had to call a few times to get it...sometimes you get someone who has no idea what they're doing. Then you call again and they give you the numbers.