In my case, going to the field office helped me a lot. Actually I was suggested by the USCIS supervisor (from the call center) to visit field office as my case has been pending long than a normal time. Normally USCIS field office entertains your case if it has been delayed a way long than it's normal processing time or in extreme urgent situation. In both cases you have to present some evidences. The field officers pull out your case in front of you and talk with the officer at the respective service center, so they can give you specific information. The officers at the USCIS field office were so nice, professional and willing to help people. I got my AP document within couple of hours. Now in your case, requesting expediting process won't work until it shall pass 90 days. And of course, current administration is taking more scrutiny in each case. You do not have other option besides to wait..Good luck