BRgirlUS

18-month Extension letter received today! 10 days after calling USCIS on Nov 20, and 4 days after USCIS sent me an email about the call. Big sigh of relief. For y'all, definitely call USCIS if you have been waiting for 30 days or longer.

I called through the military helpline last time (my husband is military), the wait was about 25 minutes and they did answer the call. The representative was very nice and I received an e-mail with a response the same day. 

update, finally got by NOA 1 12 days after calling and filing non delivery of receipt notice, waiting for biometrics again

When I was in the Adjustment of Status process, I did the interview on January 2017. 2 months after I still hadn't received my GC on the mail, neither had an answer about approval or denial. The USCIS officer had told me to wait 120 days, but I decided to get an infopass anyway. My appointment for the infopass was in April. When I got there, they told me my GC had been approved the same day of the interview in January, but somehow the GC was never actually produced... In other words, my case was "forgotten" in some corner. The result of my infopass appointment is that I finally received my GC.
So yes, it is totally worth it calling, submitting inquiries and going for infopass if you feel like something is not right.

@MariaRo, if they already scheduled your biometrics you are way ahead of everybody. Check this Forum's members Timeline list here: https://www.visajourney.com/forums/topic/685749-i-751-october-2018/?do=findComment&comment=9462832
 
Did you ask them when was your biometrics scheduled for? I believe this is the most urgent thing, If they schedule your biometrics and you don't go, it may delay your case. Also, did you ask them why it is not tracking? Which website did you use? I recommend this one: https://egov.uscis.gov/casestatus/landing.do
 
By the way the link to send an inquiry in case of Non-Delivery of Notice I posted before doesn't allow you to complete all the fields. This is the one that works: https://egov.uscis.gov/e-request/displayNDNForm.do?entryPoint=init&sroPageType=ndn

Joining the thread. Just sent my package to Phoenix.