Even if you choose to contact FBI thru either email or certified mail, yet still it won't clear your fingerprinting if that's what your motive is for contacting the FBI. Just give a serious thought that when they don't even give a shit to a request from a congressperson then what made you to think that you can pursuade them to treat your request with upmost priority if that's the motive you have in order to contact them? Just give us even a single reason as to why FBI should even give the damn to your request? Just because you pay taxes to govt., or you are good person, or your services are needed by United States, or you hold a upper hand because you have a pending N-400, or what? Don't you know how many people's fingerprinting requests are pending with FBI for such a long time? Don't you know that there is no any law as of now which can compell the FBI to clear a fingerprint within a certain time? Unless you are a person for U.S. govt interests, you have no way to speed up the clearance of your fingerprinting with them. Period.