it depends on what they asked - it could have been a scammer sending it to you, and the reply could be in your spam box. usually if they send it by mail - you are now connecting with that person by mail, so it shouldn't be filtered out.
however if they signed up for an account and sent you mail in the FAA box, they may not be getting the mail that way, which is what happened with me last week. i never heard from her again.
---Mike Savad
http://www.MikeSavad.com