Donald Trump’s campaign has not paid at least 10 top staffers, including former top aide Paul Manafort, California state director Tim Clark, former advisor Michael Caputo and two other senior aides who also left the campaign in June.

According to a review of federal campaign finance filings by Reuters published Friday, the Trump campaign has run on a shoestring budget in part by not paying its top consultants and advisors, in what the report characterized as a “departure from campaign finance norms.”

The Trump campaign called the report “sloppy at best” but did not elaborate.

Senior Trump aides Ken McKay and Laurance Gay, who left the campaign earlier this year, told Reuters via a spokesperson that they simply had been volunteering for Trump.

Caputo, who resigned after posting a tweet celebrating the firing of ex-campaign manager Corey Lewandowski, had previously told a Buffalo radio station that he had not been working for the campaign on a volunteer basis, according to the Reuters report.

On Thursday, he told Reuters that the Trump campaign still has not paid his invoices.