Democrat Congressman Leonard Boswell says his Republican opponent, Stan Thompson, is off-base to suggest he’s kept contributions from executives who worked for WorldCom, the communications giant which cooked its books to hide millions in debts. Thompson has repeatedly accused Boswell of keeping WorldCom contributions, a charge he leveled again yesterday during a radio debate in Cedar Falls. He says Boswell has received thousands from Worldcom, some of it even after the company’s executives were under investigation. Thompson says he called on Boswell to give the money back and he says to his knowledge, Boswell has not done so.But Boswell says that’s not true. Boswell says he sent the contributions back to the WorldCom Employee Assistance Fund. Boswell says Thompson is using “corporate lawyer tactics” in making the accusation.