Mr. Chung was part of the "protection" program that the Triple Threat Triad ran in his neighborhood. In order to avoid hostility, he needed to pay a "protection" fee.
On Korra's first day in Republic City, while Mr. Chung was cleaning his phonographs when he was interrupted by three Triple Threat Triad members: Two Toed Ping, a waterbender, and an earthbender. When they asked for their payment, Mr. Chung informed them that recent business had been slow and that he consequently could not pay, attempting to offer them a phonograph instead. Two Toed Ping promptly destroyed the device with firebending, claiming he "[was] not a music lover". Though he was threatened by the group's leader for his shortcoming, Mr. Chung was put out of harm's way when Korra diverted the gang members' attention.