Mmmmm! Interesting reactions and counter actions!! I like your strategies and planning. Personally myself, I have only contacted my Senator, made an online inquiry to USCIS, I don't plan to call their number or write any letters.
And like your case, l also received other letters by same address, infact the most latest one was EAD approval on August 2022. So how they couldn't deliver this time, remains a mystery!!! I also totally understand that Post office is overwhelmed right now because we're in a holiday season, but still......
I have been researching all over the thread's, on other sites such as immhelp...many other websites. But still I couldn't find any straight answers. Let's just hope for the best.