Years earlier, the firm lobbied heavily for the 2004 law that allowed the IRS to use private collectors. It had spent nearly $700,000 on its overall federal lobbying efforts between 2003 and 2006. Linebarger was hired by the IRS as part of a pilot program in 2006, but the contract ended about a year later -- before the program was nixed entirely amid controversy over the use of third-party collectors.

Linebarger says it undertakes all of its political activities with "strict adherence to the law."

While co-founder and former partner Dale Linebarger said he believes elections should be government funded, he admits that political spending is vital to a company’s success.

"The way you get access is you contribute to political campaigns, you go to fundraisers ... You make friends with these people," he said.

But even if all of the politicians and government agencies end their love affair with Linebarger, there are other private collectors that would be happy to take its place. What is really needed, consumer advocates say, is an end to the special treatment given to government debt collectors.

Until then, millions of Americans are left facing ominous threats and steep fees each year.

"They're bottom feeders; that's what they are," said Tom, the Oklahoma tax attorney. "The problem is they're bottom feeders with the power of the government behind them."