… The latest issue of Bloomberg Businessweek delves into a situation the print version of the magazine dubs “the student debt collection mess.”

Student loans have eclipsed credit cards to become the second-largest source of outstanding debt in the U.S., after mortgages. Since 2007 the federal student loan balance has more than doubled, to almost $1.2 trillion from $516 billion. The Consumer Financial Protection Bureau estimates that students, former students, and their parents owe an additional $150 billion in loans from banks and other private lenders.

With defaults climbing, lenders have turned to the courts to collect. Many of their suits are marred by missing documents and procedural errors, say consumer advocates and lawyers defending debtors. “Our office is seeing an uptick in abusive loan debt-collection tactics that leave no room for relief,” wrote Massachusetts Attorney General Maura Healey in an e-mail.

The paperwork problems echo the “robosigning” scandals that followed the housing bust. Like mortgages, student loans were bundled into packages and sold to investors. “This is robosigning 2.0 with student loans,” says Robyn Smith, a lawyer with the National Consumer Law Center, a nonprofit advocacy group. “You have securitized loans in these large pools; you have the sloppy record keeping,” as in the mortgage crisis.

The National Collegiate Student Loan Trusts are investment vehicles created by a Boston company called First Marblehead that concentrates on education lending. From 1996 through 2007, First Marblehead bought student loans from lenders including Bank of America, JPMorgan, and a bank now owned by Citizens Bank. It transferred batches of loans to trusts it created—more than two dozen in all. The trusts sold bonds backed by the loans. The trusts are responsible for collecting loan payments from borrowers and paying out interest to bondholders. In 2013 bond rater Moody’s Investors Service said it expected losses to reach as high as 50 percent in 15 National Collegiate trusts it examined.

National Collegiate trusts have been among the most active in suing borrowers, consumer advocates say. Since 2011, National Collegiate has filed more than 1,900 civil cases in Missouri, or an average of more than one lawsuit a day. The company has filed a total of more than 2,100 suits in Connecticut, Indiana, Arizona, and Oklahoma, according to state legal databases.

Mounting problems with student loan debt: Perhaps it’s another sign that college is oversold.