The transaction, however, was complicated when a neighbour knocked on the door, concerned about the commotion.
Waring's girlfriend shouted that there was a gun, prompting Coll and his associate to bolt from the address.
They were chased to their vehicle by members of the flat who threw a knife at the car as it sped away, the court heard.
The registration plate was later provided to police.
But it was Waring who found himself in trouble first.
When officers arrived at the home they found all the hallmarks of a regular drug dealer: ziplock bags, ground cannabis, cannabis plant, cannabis seeds, electronic scales and tick list noting his debtors.
Waring was sentenced in December last year to 15 months' intensive supervision and 250 hours' community work.
The day after the bungled armed hold-up, Coll was interviewed by police and admitted he confronted the dealer because he had been "ripped off".
The implement he had given to his mate, he said, was a toy gun which he had doused in petrol and burned in the bush around Pine Hill after the incident, knowing police would be after him.
Counsel Andrew Dawson said his client was willing to sit down to apologise to his victim but the man could not be contacted.
Coll, who was now managing a farm in rural Clydevale, had stressed his commitment to changing his life's direction.
"It's a question of whether you're going to walk the talk or you just talk," Judge Kevin Phillips said.
Coll was sentenced to six months' community detention, 180 hours' community work and nine months' supervision.
It was not the first time Waring had got himself in strife over a drug deal gone wrong.
In 2018, he took $400 from a French couple and failed to supply them with cannabis, resulting in them taking violent retribution.
As well as the beating, he was sentenced to community detention and intensive supervision.
