I am currently pending I-485 (EB3, skilled worker employment based, priority date Oct 2008) since April 2014. I submitted inquiries through congressman, they received a letter that my case is on hold indefinitely. Do you recommend filing Writ of Mandamus or would that cause a denial? What other actions can I take, I've submitted a case through the Ombudsman and met with a USCIS officer through Infopass appointment (who told me nothing). No RFEs have been issued for this case, I-140 was approved and fingerprinting done (twice, since first set expired).
See clip from Attorney Rajiv S. Khanna's conference call video that addresses this question.
Writ is simply order of the court or a formal order.