What a MESS! Talk about the right hand not knowing that it is attached to the same body as the left hand.
Sounds like you've done everything right at this point. No idea about any ADA impact on credit reporting, though I would be interested to know if the ADA could possibly impact credit reporting. Have a feeling it doesn't.
So it sounds like where you are right now is in an appeal with the Registrar. No clear next step, but this is what I would do:
~CMRRR letter to the actual registrar explaining that your case is in appeal, but you haven't heard anything yet, and we're now almost to the fourth quarter of the year. Please let me know if you need any further information or documentation from me. This situation is particularly disturbing because this is showing an unpaid debt on my credit report, and severely impacting my ability to get credit. I fulfilled my responsibilities to the school in 2005, and have been shocked at the lack of communication between departments. The appeal should be resolved in my favor, and the university should remove all reference of this unfortunate internal miscommunication from my credit reports as soon as possible.
~CMRRR letter to the university president (and any other VP-like the Office of Student Relations-you can find) outlining the whole situation. Use paragraphs, and explain step by step. Explain that you are frustrated by the lack of progress in resolving your appeal in the registrar's office. This situation is particularly disturbing because this is showing an unpaid debt on my credit report, and severely impacting my ability to get credit. I fulfilled my responsibilities to the school in 2005, and have been shocked at the lack of communication between departments. The appeal should be resolved in my favor, and the university should remove all reference of this unfortunate internal miscommunication from my credit reports as soon as possible.
Keep at it until they resolve. This is an internal university problem, and you just have to get to the right person to make the departments talk to each other.
I don't think I would go the traditional route on this--the DV's with the CA, all that. I would stick with harassing the univ administrators until they fix it.