In the suit, Kuehn said the defendants violated the "customary and usual business practice" of reducing the principal balance and maintaining the monthly payment amount when extra payments are made on a loan, "thus substantially lowering interest costs."
According to public financial aid service, FinAid.org, all federal and private student loans allow for penalty-free prepayment to pay off the balance of the loan.
He said he called the Student Loan Corporation's customer service phone number twice on January 4 and was told he could not return his monthly loan payments to the original amount.
"The [customer] representative refused to return plaintiff's monthly payment to the original amount," the filing stated.
"I tried to resolve this with them and they were not open to it," Kuehn told ABC News.
Until the company responds to the lawsuit or his concerns, Kuehn said he continues to make the lower monthly payment on his loan.
"I'm trying to figure out what's going on," he said. "Initially you just want the problem fixed and then you realize there is no communication on their end, so you're forced to take action."