With less than a month before federal student loan payments restart after the years-long pandemic pause, many borrowers are having a hard time connecting with their loan servicer.

Some are having to wait hours on hold to find out how much they owe, what day their first payment is due, or to make an early payment to avoid paying interest -- which resumed accruing on federal student loans on September 1.

And servicer websites, including Aidvantage and Nelnet, have been sporadically down over the past week as high volumes of borrowers try to access their accounts.

Danika Wahlin, 28, is hoping she qualifies for a $0 monthly payment under the new income-driven payment plan known as SAVE (Saving on a Valuable Education).

But it's only her best guess, because her payment amount is not available when she logs in to her loan servicer, EdFinancial Services.

EdFinancial is transitioning to a new loan servicing platform, and, according to a message Wahlin received last week, is "still working on getting" her loans into its new system.

"Not knowing how much I'll be paying has been a huge mental stressor on us," said Wahlin, who has student debt from both undergraduate and graduate school.

Her wife recently started graduate school, creating a tight budget for the couple.

"Our finances are stretched extremely thin as it is and having to pay any additional amount is going to put us in real trouble," Wahlin said.

EdFinancial and Nelnet did not respond to CNN's request for comment. Aidvantage's parent company Maximus referred CNN to the Department of Education. The Department of Education did not immediately respond to a request for comment.

An unprecedented restart of payments

Bringing roughly 28 million people back into repayment at the same time is an unprecedented task and was bound to be a bumpy process.

Interest has already restarted and monthly payments will begin in October, though the exact due date varies by borrower. Like before the Covid-19 pandemic, borrowers will make their payments to student loan servicers that are hired by the Department of Education.

But it's been more than three years since most federal student loan borrowers have been required to make a payment. The freeze went into place in March 2020 and was extended several times before Congress prohibited another delay.

Millions of people who finished school during the pause are making their payments for the first time. Many others have different loan servicers now than the last time they made a payment because several companies ended their contracts during the past three years.

Plus, lawmakers left funding flat for the Federal Student Aid office, which oversees the financial aid system, despite its bigger workload this year. The office got about $800 million less from Congress this year than what the Biden administration had asked for.

On hold for hours

"I have hit the three-hour mark," said Marlee Lane, as she was on hold Wednesday with her student loan servicer EdFinancial for the fourth time in two days.

She called the day before at breakfast, again at lunch, and then asked for an automatic callback but said she never received one.

Lane, 32, wanted to pay off her balance before payments restart in October so that she can avoid paying the interest that will accrue throughout September. But when she logged into her servicer account, the system would not let her make a payment.

She had hoped to qualify for President Joe Biden's student loan forgiveness plan before payments restarted, but the program was struck down by the Supreme Court in June.

"I can pay it all off now and I'm trying to do that so they don't make another penny off me," Lane said.

After waiting on hold for four hours, an EdFinancial representative finally answered her call. She learned that her loans are in a forbearance that she was previously unaware of. She'll have to opt out before making a payment.

Repayment is becoming a 'scary mess'

Danielle Dodder, 48, has also made several attempts to connect with a customer service representative at EdFinancial. While she is able to log in and see her upcoming payment information -- the amount due is higher than what she expected, without explanation.

"It's honestly a scary mess now and the process is completely opaque," said Dodder.

What's also confusing for Dodder is that the EdFinancial website is prompting her to receritfy her income in order to remain in her income-driven repayment plan. But, according to the Department of Education, borrowers should not have to recertify until at least six months after the pause ends.

Income-driven repayment plans can significantly lower a borrower's monthly payment by calculating it based on their income and family size, regardless of the amount of debt they hold.

"I have no idea what's actually going on with my loan," Dodder said.