"The defendant ripped open the front door of the building and threw multiple punches at the victim," Butler said.
"The defendant then tackled the victim to the ground inside the building and they grappled on the ground until the victim pushed the defendant out the door."
The two then grappled each other on the concrete outside and Gartner struck the victim in the side of the head with his knee and punched him multiple times.
"The defendant became tired and stopped assaulting the victim, the defendant got up, gathering his belongings and left in a vehicle where he was stopped by police a short distance from the scene."
Raukawa Simon was the lawyer for the defence.
"There's a bit of a background in terms of this state of affairs, after a friendship of about five years, this incident occurred because Mr Gartner didn't get his money returned," she said.
"He's here to take responsibility, he was in a time of stress and he does want to move on."
Judge Barkle said Gartner had no history of offending before this matter.
"Mr Gartner I don't know what's behind the $200. Regardless, it doesn't justify this sort of action.
"Your penalty will be 120 hours of community work."