If your case has been unreasonably delayed and is outside normal processing times, it is sometimes necessary to file a lawsuit against the U.S. government. Filing suit in federal court against USCIS, the State Department or individual U.S. Embassies is often an effective way to get cases moving again that have been stuck.
Typically, the best approach is to seek relief under both the Mandamus Act and the Administrative Procedure Act (APA).
When Should I Consider Suing the U.S. Government?
What Types of Lawsuits are Possible?