 Each month, about 71 million Americans, retirees, disabled workers, and others receive checks from Social Security. But as we first reported last fall, each year about a million people get something else in the mail, a bill. They're told they owe the government money, sometimes tens of thousands of dollars, because the Social Security Administration miscalculated their benefits and paid them too much. It can happen to anyone. It can take years, even decades, for these unexpected debts to suddenly come to light.