This from another legal site (not credit repair, simply lawsuits and settlements)
While some students may be able to take advantage of federal education loans to pay for college—such as Perkins loans or Stafford loans—many students turn to private education loan companies in order to finance their education. Some student loan lenders and servicers, including NextStudent and ACS, face allegations of denying loan payments or claiming payments were not made even though customers have records of those payments; not issuing adequate student loan statements; charging multiple late fees even though the payment has been processed; and retroactively assigning interest to payments that were allegedly missed, some a few years before.
At least one student loan class action lawsuit (case number 1:2012cv06583; Brietman v. Affiliated Computer Services, Inc. et al) has been filed against both Affiliated Computer Services (ACS), a student loan servicing company, and NextStudent which is a student loan lender, as well as US Bank, alleging they aimed to keep borrowers trapped in student loan debt. The plaintiff alleges she tried to make extra payments to pay down her principal balance, but those payments were redirected to cover interest and regular monthly charges.
Meanwhile, a student loan second lawsuit filed against ACS by Joshua G. Fensterstock—also alleging extra payments were put towards interest and not the principal balance—was reportedly sent to arbitration by the judge.
There is also a lawfirm investigating ACS for wrongful application of payments, illegal consolidation of student loans, usurious interest rates, and more. I would encourage everyone who has problems with this company to reach out to the lawfirm (Google is your friend here).
My lengthy issue with ACS and student loans in general is too arduous for this forum (and I don't have enough blood pressure meds to stop me from having a stroke!!). Suffice to say::
Original loan amount: $22,000 (1993; 9.2% interest)
Total owed now: $175,000 (2015)
Reason?
I deferred while in school, deferred while unemployed, raised my son on my own with limited child support, took care of my elderly parents AND ... oops, there goes my BP! 
When I requested an IBR from ACS, I was denied 3x by the customer service rep in 2012, and 5x this year due to "document issues" ... escalated to manager who then told me which boxes to fill out and what to put down ... I FAXED that to her, she then sent me a copy of SOMEONE ELSE's documents (guy named Jason)....
BTW, if you are wondering if I ever paid anything?
For 5 years, I paid $950 a month + to pay down the loans and ... all of that was applied to interest, NONE to principal.
And none of that was tax deductible because I "made too much money" ...
(LAST: IF MY COPY/PASTE FROM ANOTHER SITE IS NOT APPROPRIATE, PLEASE REMOVE - I APOLOGIZE)