We are in the same unfortunate boat as many of the other April filers without receiving the receipt notice...definitely not fun.
Fortunately after multiple calls with USCIS and a few tier 2 calls we were able to get an ADIT stamp for my wife last Wednesday. One officer we spoke to basically said we could only get an emergency appointment if we got a letter from her office requesting verification of status (eventhough we know that’s not required). That worked like a charm.
Got the call about scheduling the appointment, explained the situation, then got an email requesting a PDF of the letter for verification, and a day after sending we got a call for an appointment the next day. So we got the stamp, but now will have to try some of the other tips from this thread to get our receipt notice as we’re approaching the 30 day mark on the first non-delivery notice.
Also heard a few interesting things from some of our conversations with the more helpful officers...They confirmed a receipt notice was never printed and that they saw a similar large scale issue like this a few years back with people ultimately getting the letters but a few months late. They also reassured that even without the stamp or letter, she was still in status since the case is pending (which was good to hear as one officer was trying to tell her she couldn’t stay working, etc without the stamp or letter).
hopefully this all gets sorted out soon with letters and/or stamps for everyone that needs them!