I agree with everyone when they say ask for the supervisor, but don't let them say, She is busy. You then have your next response, say who am I speaking with and when can I expect a response from your supervisor? Also ask for the super's voice mail and extension. When you are told anything like I can' tell you, I can't give you that information, tell them to write that response down and you will be there to pick it up in writing, trust me, they'll help you then.
If they say they are waiting for a certain doc. from him, tell them you will be there to pay for return receipt postage so there is a date stamp, I am 100% sure they will say that's not necessary. You can also tell them you want an income verification form, possibly available on line, and you mail it return receipt requested to his employer. You have to have an ASSERTIVE response ready for everyone of there door shutting comments.
If all else fails, call your congressman, that is their job, to help you! Develop an I am going to get my money this week attitude and don't take NO!
In NC you can go back 3 years BUT you have to have all receipts so basically it is there way of shutting you up.
PS - going there in person is best. If they say you don't have an appointment that they can't help you, tell them you want an answer and you are NOT leaving. Worse case if they wont help you, write the super a note, have them stamp it received and make you a copy.
Good luck.
M.