Which division of FOIA can I get a copy of lost H4?

H-4 approved notice is lost and now is asked for 485 RFE (maintaining non-immigration status). I looked through FOIA website and it seems that divsion of the Executive Office for Immigration Review is more relative. But when I called them and was told that they don't have such records. Anyone knows which specific department I can ask for the H-4 approved notice!