CeeLo Green -- Concert Promoters REFUSE to Pay Over Short Show

Diminutive rapper CeeLo Green came up short on Saturday night and it's apparently going to cost him ... because a concert promoter in Arkansas is refusing to pay him.

Green performed at Riverfest in Little Rock, Ark. on Saturday night. Green was contractually obligated to play for at least 75 minutes ... but his performance only clocked in at around 40 ... at least that's what Riverfest board member Cheddy Wigginton tells TMZ.

Wigginton said they had to pay nearly half of Green's fee up front -- they're withholding the rest. He said Riverfest won’t be looking to recoup the deposit.