@Lymen or to anyone who's in the same boat, these are the ff. email address where you can follow up your case, depending on your service center.
Please have available your receipt number, alien registration number, type of application filed and date filed.
California Service Center: csc-ncsc-followup@dhs.gov
-Vermont Service Center: vsc.ncscfollowup@dhs.gov
-Nebraska Service Center: ncscfollowup.nsc@dhs.gov
-Texas Service Center: tsc.ncscfollowup@dhs.gov