Verbena Burgess broke out into song on Sunday night, and was pelted with insults by a crew of young men outside her home on Morris Ave. in the South Bronx, the sources said. "She was singing. They came from across the street and started telling her, 'Shut up, shut up,' " said a neighbor. "She said, 'I'll call the cops, or I'm going to ring the bell and get my sons.' They told her, 'Do it. Call the cops. Call your boys.' "