[SaveUncleSam]

I have been using the method talked about by Robert Menard on the Google Video entitled, "Bursting Bubbles of Government deception" concerning parking tickets.
I received two parking tickets last Dec and Feb and have written letters with a timely return of the tickets R4C to the parking office. They responded with a statement of charges, saying my "appeal" was denied. I then asked for a "bill", saying that I cannot pay a debt without evidence in the form of a signed bill. I also asked for a copy of the contract signed by me, agreeing to these fines and fees. I received a letter back from the hearing officer saying that she enclosed a statement for me and that she hoped it would satisfy me. I sent her a letter back saying that I had not received what I had asked for.
They responded by sending me a brochure for the Parking Office detailing the parking lots, permits, etc., but not a personal letter this time.
Now I have been barred from registering for classes until this $90 is paid up. They looked into the University computers and matched up my name and address (I assume) so see that I am a student at the University (not merely a visitor) and have contacted the Registrar's office to bar me. What can I do about this? I have heard something about the US Code part concerning lawful money (this method aparently works), but I am not sure what part it is and how to use it.
Classes start next Tuesday and I would hate to miss any classes. They have essentially ignored my request and have instead threatened to ruin my academic career... help!