An estimated 30,000 student loan borrowers thought their private loans were discharged when they declared bankruptcy years ago — but their student loan lender, Navient, disagreed.

Navient continued collecting for those loans, and now the borrowers are suing in the U.S. Bankruptcy Court for the Eastern District of New York.

"We began these cases in 2016 at a time when there was some confusion in the law regarding what types of student loans couldn't be erased in bankruptcy,” Austin Smith, one of the attorneys representing the plaintiffs for the case, told Yahoo Finance. “Since that time, more than a dozen courts across the country have agreed with us that these types of student loans are dischargeable and rejected Navient's increasingly irrational arguments that have sought to prolong and delay this process.”

The want Navient to stop collecting on the already-discharged loans and compensate the borrowers for what’s already been paid.

Read more: How to repay student loans: The full breakdown

The case strikes at the heart of two issues: The fact that certain types of student loans are in fact dischargeable in bankruptcy — a myth that’s slowly beginning to unravel — and that Navient had engaged in deceptive behavior which harmed borrowers.

“We have tried informally to get Navient to stop, and they have refused to stop,” Smith added. “And Navient refuses to stop because it believes that the profit to be earned today exceeds whatever nominal penalty is imposed tomorrow for violating the law. We are now asking the court to make Navient stop, and stop now.”

If they win, attorneys involved in the case estimate that 30,000 borrowers involved in this case with these “loans” that are in limbo would see financial relief while 250,000 to 500,000 borrowers with similar loans from other lenders nationwide could also benefit.

Case carries heavy implications for almost 500,000 borrowers

The issue arose more than a decade ago, when a student loan borrower filed for Chapter 7 bankruptcy and requested for a discharge of his student loans. The borrower had owed slightly more than $12,000 to Sallie Mae, which today is known as Navient. The court had ordered discharge of those loans in 2009.

The borrower argued that while generally education loans are not dischargeable in bankruptcy, his case met one of two exceptions: That the loans were not used for qualified education expenses. (The other condition was that the debt, including government-issued loans, was causing “undue hardship,” which was is currently being adjudicated in another case.)