A debt collector that purchased credit card debts from NAB and then threatened borrowers with legal action in the bank's name has been found to have engaged in misleading and deceptive conduct by the Federal Court. Justice Nye Perram also found the firm engaged in undue harassment and coercion.The case dealt with the activities of Accounts Control Management Services in relation to its dealings with eight debtors between 2009 and 2010. ACM bought the debts from NAB (and, in one case, from Commonwealth Bank) at discounts of between 79 per cent and 99 per cent of face value.The Australian Securities and Investments Commission brought the case against ACM following a campaign by the Consumer Action Law Centre.In the cases considered by the court, ACM would frequently make untrue claims of either referring a case to solicitors or of having instigated legal action. ACM staff also contacted employers and family members about people's personal debts.The debt collector had around 500,000 open accounts at the time of the conduct under review by the court. It has 275 staff.ACM - controlled by its founder, Humberto Vieira - was taking steps to prepare its business for a listing on the stock exchange at the time, a plan it later abandoned.