Question Ref Credit Rating and true reporting

Okay, I went to refinance my car today and was told my credit rating was down because I.S.A.C. (that is Illinois Student Assistance Commission, they run the student loans thru Illinois where I went to school) was reporting an "I-5" entry on my credit that I was behind in excess of 120+ days on my loan..... Which is completely BS at this point.......I was and have been behind in the past, but I am current as of this time, and it has been at least 2 years or more since I have missed a student loan payment...... I called them and they said it would stay on my credit for 7 (SEVEN!) years!  How the hell can they get away with this?  Isn't there some fairness in reporting law?  Can I call the credit bureaus and debate the truthfulness of this and get I.S.A.C. banned from reporting bad credit based on their fraudulent reporting policies?????  I called ISAC and got shuffled all over hell until I got someone's voicemail where I left a nasty voicemail, and of course they have not been in any rush to call me back.......So, how the hell is this fair when I am being honest and forthcoming with them and paying my bill every month faithfully for over two years??????? I appreciate any help from anyone working in the credit or loan fields in advance....