Income taxes Collectors don’t help IRS Private debt collectors cost the IRS $20 million in the past fiscal year but brought in only $6.7 million in back taxes, the agency’s taxpayer advocate reported Wednesday. That was less than 1 percent of the amount assigned for collection. What’s more, private contractors in some cases were paid 25 percent commissions on collections that the IRS made without their help, according to the annual report by Nina Olson, who heads the Taxpayer Advocate Service, an independent office within the IRS.