I advise you to call your local congressman office and ask to talk to the USCIS Liasion. They can really move your case quickly, if it has been a pending status for longer than it should be Or if you have an emergency for which you need to move the case quickly. I have done it a couple of times (for my and relatives cases), and they are always been helpful with positive result every single time. They provide this service for free for people living in their area.

Just google "your zip code - congressman office" it will show up. Be sure to contact the congressman, not the senator.