I-485 process not understood!!!?

My company applied for a green card for self and family (self, spouse and two children). After the due process in October 2004 all of us got our cards EXCEPT my youngest son. I visited the local immigration office at least 6 times and they are themselves supprised why he has not got it. They sent e-mails to their head office for an answer but nothing. I wrote several times to the BCIS and they did not have the courtsey of a reply. He is a bright kid and is missing out on most scholarships at the university because his status is in a limbo. I even contacted the local congressman and have come to know that currently the processing for I-485 (adjustment of status) for EB3 (India) is April 2001 - I have been monitoring the Visa bulletin and the processing dates just doesnt seem to move. My question is: if the green card process is family based and we got ours, why one child gets left behind and the processing date jumps BACK by 2 years. What can I do to expedite his?