If you filed with an attorney, ask them to follow-up with USCIS.
Unfortunately, you cannot even setup infopass appointment anymore to check and meet them in person https://my.uscis.gov/en/appointment/v2 …
Call the USCIS contact center again in few days and see, if they have anything…
It is not very common, but at times, mail gets missed and things happen…
Do update, how it goes, after you have sorted it out here for everyone benefit.
You are correct Kumar. Infopass option no longer available.
I will update on my case later.
Please let me know if there is any way I could expedite this so that atleast I have the receipt notice in hand soon.