For Jennifer Dahlke of Minneapolis, what started out as $2,073 worth of overdraft-related debt turned into a $4,312 nightmare that wouldn’t go away. On Wednesday, Minnesota Attorney General Lori Swanson filed suit against Bradstreet and Associates, an Edina-based debt collection firm. She accused the firm of charging up to 21.75 percent interest on consumer debt, though a Minnesota law caps the interest rate at 6 percent. Dahlke is one consumer who was pursued by Bradstreet, but her situation isn’t unique. Since 2009, Swanson said, Bradstreet has bought $18 million in debt from U.S.