Christopher Lewis was slapped with a $525 ticket at lunch Wednesday at a Veteran Affairs Hospital in Charleston, South Carolina.
There are signs in the cafeteria telling people refills are not free.
Lewis, who was doing construction work there, says he never noticed the signs.
A federal police officer gave him a ticket for shoplifting and banned him from the premises.
"I want everybody to know that I made a simple mistake, that I'm not a thief, that I'm not dishonest," Lewis said. "I'm trying to do the right thing."
Lewis says he wasn't given a chance to pay for the refill.
He planned to fight the ticket in federal court, but late Thursday the medical center decided to drop the fine and allow him to come back to work.