After months of waiting, U.S. importers will finally have access to the $166 billion collected from tariffs that were ruled unconstitutional. But as American small businesses battered by the import taxes look to recoup the cost of the levies, they may find it’s more difficult for them than it is for larger, wealthier firms.

On Monday, U.S. Customs and Border Protection (CBP) rolled out the first phase of its electronic tariff refund system, also known as the Consolidated Administration and Processing of Entries (CAPE), allowing importers to apply for refunds on tariffs struck down by the Supreme Court.

The justices ruled in February that the duties imposed under the International Emergency Economic Powers Act (IEEPA) were illegal, but gave no recommendations on how to provide refunds for companies that paid for the brunt of the import taxes, leaving the process to the Court of International Trade and CBP.

Of more than 330,000 U.S. importers, about 56,497 have applied for refunds, according to recent filings from CBP. Claims from those importers total about $127 billion. CBP said refunds are to be distributed 60 to 90 days after they are processed.

Small businesses were hit particularly hard by the levies. A Federal Reserve survey published last month found 42% of small firms called rising costs owing to tariffs a primary financial concern. These smaller businesses, which operate on tiny margins, have a harder time stockpiling inventories or eating tariff costs to avoid passing down higher prices to consumers. A March report from the Center for American Progress found small businesses paid $306,000 in tariffs on average last year.

But unlike larger companies—such as Costco and FedEx, which have already sued the Trump administration to ensure eligibility for refunds—smaller businesses often lack key resources in navigating the legal intricacies and uncertainties to secure the refunds, jeopardizing their ability to recoup the hundreds of thousands of dollars they lost in the past year.

“Especially given the uncertain legal environment that we’re operating in right now, I am deeply worried that small and medium-sized importers are going to end up losing their refund rights because they haven’t had access to trade counsel to help back them through it,” Matthew Seligman, founder and principal of Grayhawk Law and a federal litigator focusing on constitutional law, told Fortune.

Small businesses’ unique tariff challenges

For small businesses, the refunds have been just part of the headaches surrounding tariffs. In many cases, owners lack the personnel and bandwidth to closely track legal and compliance issues, said Dan Anthony, executive director of We Pay the Tariffs, a coalition of small businesses opposing the administration’s tariff policies. For many of these companies, looking into tariff refunds means diverting resources away from new products and growth.

“What you end up with is small-business owners or someone who does product development, who is now expected to be a tariff expert,” he told Fortune.

Small businesses also are navigating tight cash flows and lack of liquidity, Anthony explained. When importers bought products from overseas, they may have made advanced payments to vendors to lock in lower prices before tariffs went into effect. But the stockpiling may have resulted in an inventory surplus whose costs took months to recoup, he said.

Anthony added he spoke with small-business owners who have increased lines of credit and even taken out a second mortgage on their house, so promises of refunds have become a lifeline.

Some companies with a larger risk appetite have opted to use refund claims as collateral for loans or to sell the rights to claims outright in exchange for immediate cash.

But according to Anthony, small businesses are more likely to take a “wait-and-see” approach to the tariff refund process to figure out which strategy will get them the largest chunk of change.

“That’s money that they need to come back so they can climb out of that debt,” he said.

Tariff refund headaches

The many legal question marks hanging over the tariff refund process make it even harder for small businesses without resources to parse through the ins and outs of the refund system, Grayhawk principal Seligman said.

Among the challenges is the tight time frame for applying to CAPE. At this time, refunds are available for “unliquidated” entries—meaning CBP hasn’t made a final determination on how much is owed—or on entries “liquidated” in the past 80 days, where CBP has determined what is owed. Businesses with those already liquidated entries have to file immediately or risk being ineligible for refunds if they time out of the 80-day window.

Ineligible companies will likely either have to file a formal protest with CBP or sue in the Court of International Trade for refunds, though the government hasn’t made the necessary processes clear, Seligman said. He indicated that smaller businesses without legal counsel may not be aware of or prepared to take these next steps should they be ineligible for CAPE.

Seligman noted there is still plenty of uncertainty around whether the refunds will even reach importers. The Trump administration may choose to appeal the Court of International Trade’s order that the government must dole out universal refunds, which Seligman said would render applying to CAPE “sort of a waste of time.” He added that some of his clients have experienced technical difficulties with the portal and have received error messages on attempted submissions.

CBP did not immediately respond to Fortune’s request for comment.

“These types of glitches, again, are not just delays,” Seligman said. “They are delays that can lead to ineligibility, and potentially—if importers don’t have appropriate counsel—can result in permanent loss of refund rights.”