I held a TS SCI w/FS with NSA and resigned from company I worked for on Feb 28, 2008.  When I resigned there were no problems or issues open or identified to me. I applied and was accepted at a new company in July 2008. The FSO submitted my paperwork to get my clearance reinstated and was told my contractor clearance that there were some unresolved issued with my last employer and contractor clearance would not grant reinstatement until an investigator conducted a personal interview. Contractor clearance would not provide an additional information on the matter because of privacy matters but told the FSO that contractor clearance was backed up and it could take several months before an investigator could conduct the interview. I tried to inquire with my previous employer but have not received any responses. I called NSA and all they would tell me is that I need to work through my FSO. I am looking for advice on how to 1) find out what the unresolved issues are 2) get the process of my reinstatement and the personal interview moving along.