After opening his bill from UNC Health Care, Charlie Caserta quickly decided that he wouldn't pay. Caserta had paid a $50 co-pay for his visit to a liver specialist, and was hopping mad to see that UNC was trying to collect a $152 facility fee. UNC Health Care collected by pulling the money out of Caserta's state tax refund. It used a little-known law, the Set Off Debt Collection Act, that allows state and local agencies to collect debts by seizing state tax returns and lottery winnings. The law has been good to UNC Health Care. Last year, UNC Hospitals collected $5.7 million, while UNC Physicians and Associates collected $2 million. Together, that accounted for 11 percent of the $72 million of set off debt collected for all state and local agencies that year.