James Miller,
Keep on them. When I submitted a FOIA request, all I received was a copy of all my correspondence to them.
BTW, I was doing some estate planning, so I contacted OPM to obtain information regarding my retirement benefits. I was told that there was no record that I had ever worked for ATF. Even though I was not of retirement age, I thought that OPM could at least confirm the more than 15 years that I contributed towards FERS retirement. I was directed to contact ATF HQ. After many months of being passed around, I was able to get someone from ATF to send in the proper paperwork to OPM that acknowledged that I had retirement benefits.