The first time Tiffany McDowell, 36, called the U.S. Education Department in February, she was quoted an estimated wait time of 50 minutes.

Frantic to get answers about why her nearly $9,500 tax refund was seized to pay down her student loans, McDowell decided to hold. A few minutes in, the call dropped. McDowell called back. Minutes later, the call dropped again. This went on for days before she finally got someone on the phone.

“It feels like they’re trying to discourage you from getting help, the way everything is drawn out,” said McDowell, a customer service manager in Bedford, Tex. “It shouldn’t be so difficult to get someone on the phone.”

McDowell’s experience is not uncommon. Other student loan borrowers complain of being disconnected or holding for hours after calling the Education Department about money being withheld from their income tax refunds, known as a tax offset. Consumer lawyers acknowledge that it often takes a little longer to get through to the federal agency during tax season, but they say the current breakdown in communication is unprecedented.

“In eight years of representing borrowers and dealing with the Education Department, I have never seen this before,” said Adam Minsky, a student loan lawyer in Boston. “I have never seen such a widespread, long-running, systematic breakdown of the Education Department’s default servicing system.”

A backlog of security clearance reviews has left the Education Department units that handle defaulted federal student loans short-staffed. The delay also has disrupted staffing at some private collection agencies that recoup past-due debt for the department.

Employees are being cleared, but not enough to resolve the call center disruptions. That means people who are severely behind on their student loan payments may find it harder to reclaim their refunds or stop the federal government from garnishing their wages or Social Security. What’s more, the disruptions could delay struggling borrowers from getting back on track through loan rehabilitation.

As of September, an estimated 7 million people had not made a payment on federal student loans for nearly a year. That amounted to $140 billion in unpaid loans — a 17 percent increase over the same period a year earlier, according to the latest data from the Education Department.

Federal student loans are treated as being in default after 360 days of delinquency. At that point, the loan is transferred from a servicing company to the department’s teams: the Default Resolution Group and the Debt Management and Collections System. Because those units don’t have the staff to handle the volume of loans in default, private collection agencies pick up some of the slack.

Still, the Education Department’s teams are the primary resource for people to dispute levies against their paychecks, Social Security or tax refunds. They also help some borrowers enroll in student loan rehabilitation, a federal program that erases a default from a person’s credit report after nine consecutive payments.

Because the units play such critical roles, the long wait times and disconnected calls leave people with little to no recourse to ease the burden of default. Few people can spend hours on hold during the workday, so getting help could take days or weeks.

Nearly all federal agencies are contending with security clearance delays. The long, involved process has created a backlog of hundreds of thousands of cases throughout the government. But the process became more complicated for the Education Department’s Office of Federal Student Aid after an audit by the agency’s inspector general.

The watchdog found contractors who were working for the division before their background checks were completed, which led the agency to add more layers to its screening process. People familiar with the situation who are not authorized to speak publicly say the new system came into full effect at one of the busiest times of the year: tax offset season.

The Education Department declined to comment, while the Office of Personnel Management, which plays a key part in background checks, referred all questions to the department.

“When people are living paycheck to paycheck, this isn’t just an annoying bureaucratic disruption. This impacts people’s ability to pay for food, housing and medicine,” Minsky said. “There are real consequences for real people, and the Department of Education’s handling of this is just shameful.”

By the time McDowell reached someone at the Education Department, the mother of two was facing eviction. Months of unpaid maternity leave left her struggling to pay rent. Late fees piled up and eventually placed her in arrears. She desperately needed her refund.

Staying current on her student loan payments was never easy after McDowell dropped out of Kaplan University with more than $10,000 in debt. She defaulted but tried to get back on track through loan rehabilitation in November. McDowell said she later learned that her loans were already flagged for an offset before she entered rehabilitation.

In light of her pending eviction, McDowell said the representative at the Education Department suggested that she apply for a hardship refund. But he warned that it would take at least a month for the case to be reviewed and an additional 45 days for a refund. By then, she might be out on the street.

“I’m trying to work something out with my landlord,” McDowell said. “I know I owe the money. I know I went to school. I get it, but the entire refund? Even if they’d taken some of it, I could have used the rest to pay my bills. I’m a single parent. This just messed me up a lot."