Called the number back from another phone. There was an automated message which said that the number is an old, invalid number for Social Security office. I believe this is correct, as I have been waiting for them to contact me. Sent them two letters and left two voice mails for them over the last four months. Very frustrating that they would call me from a number I cannot call them back on. They now use an 800 number instead that you can call, but you cannot get through to anyone unless you know their extension. Even if you know the party's extension, it still goes straight to voice mail.
Received a call from this number looking for my friend who has filed for disability. Said she was trying to get in touch with her and would keep trying. I let my friend know they were looking for her.