@Jaysmi, a congressman has a couple of offices around the area including one in DC. And every single congressman has a USCIS Liason whose job is to straightly contact USCIS and find details that you cannot get from Infopass.

Once you contact the USCIS Liason, they will email you an authorization form which you need to sign and send them. This is your consent for the Liason to discuss your issue with USCIS. That form will have a space to write what exactly are you trying to find out from USCIS, and what type of help do you need from Congressman's office. In one of my relatives case, it was a document they have requested which we already submitted. We went to Infopass, they asked for it again. This would have just make the process long, so we contacted congressman to ask USCIS to look at the previously submitted document properly (Infopass will not take a request like this). Liason asked USCIS to do that and within a week we got an email saying USCIS found the document and case moved forward without we having to do anything. In another case, we needed to get a citizenship faster for a very particular reason. Liason asked USCIS to speed up the process and got the citizenship from application to swearing within 1 and half months (disclaimer: the reason was very compeling. They do not do it for cases like "because I need to marry and bring my wife ASAP")

Anyway, from this point, you can just send all the documents meant for USCIS straightly to your congressman's Liason office and that person will mail/fax/email to his contact person in USCIS. They kind of act like a "free assistant" for you. It is unbelievably helpful. I would say 100x better than Infopass. I have exclusively relied on Congressman for my USCIS hiccups rather than dealing with USCIS myself or bothering about Infopass.