Commonwealth and Norfolk have built a reputation for operating at the hard edge of this increasingly aggressive and methodical trade.

It is a business with many reputable players, firms that collect money zealously but rarely cross the line of fairness. And then there are those that seem to live by another set of rules.

Commonwealth, owned by 41-year-old Chad Goldstone, and Norfolk, owned by his brother Daniel, who is 44, are among the most active users of the state's small-claims courts, where lawsuits are limited to $2,000 or less. Together, the two firms have filed about 12,000 lawsuits in each of the last four years in all but two of the state's 70 local courts, according to records examined by the Globe. That is more than 10 percent of the state's small claims caseload.

And as for car seizures, a tactic many collectors consider harsh and unseemly, the Goldstones have made it an everyday practice.

''The way he handles cases offends us,'' said Richard S. Daniels Jr., the owner of a large Boston collection law firm, speaking of Daniel Goldstone. ''His practice is abusive.''

Seizing cars to collect old debts is lawful in Massachusetts. But time and again, those working on the Goldstones' behalf have turned it into an excruciating ordeal for consumers, making dark-of-the-night collection visits, and holding cars hostage until debtors can scrounge up the cash to pay down a past-due amount.

Almost always, debtors who have their cars towed wind up paying far more than their original debt. Part of that is interest, of course. But it is also the result of hefty fees charged by the people who work on the Goldstones' behalf, the kind of people Dimanche found knocking at her door just after dawn - locally appointed constables, deputy sheriffs, and tow lot operators.

And in cases where debtors are unable or unwilling to pay the debt, plus the high seizure, towing and storage fees, their cars are often auctioned for a fraction of their market value. Or they are junked, leaving the debtors without transportation and still liable for most, or all, of the debt.

The sight of a tow truck at the door is unsettling enough. But for some debtors chased by Norfolk and Commonwealth, it is literally the first they have heard that they are being sued. In several lawsuits examined by Globe reporters, Dimanche's among them, the two companies provided incorrect addresses to the courts, with the result that judgments were issued without the knowledge of the debtors. But finding the right address is seldom a problem for the constables and sheriffs Norfolk and Commonwealth hire to seize debtors' cars.

As Dimanche said in a hand-written plea to the court days after her car was taken: ''I, Marie Dimanche, was never notified of any court hearing, and a judgment was passed without my presence to defend myself.''

But no court motion could fully describe what Dimanche had lost. The day she handed over her keys - her only means to get to work and her children to school - was the last day she would ever see her car.