The University of Miami Hospital will have to refund $3.7 million to Medicare after a federal audit of the hospital's billing practices found the hospital overbilled in 2009 and 2010, according to a report released Tuesday by the U.S. Department of Health and Human Services Office of Inspector General. UM issued a statement Tuesday saying the university is working "with the relevant federal agencies to determine the correct amount owed for billing inaccuracies." In July, UMH Chief Financial Officer Darryl Caulton filed a letter contesting the inspector general's method for calculating the refund to Medicare, saying the hospital "disagrees" with the way the figure was determined.