"I thought she was joking," Sheppard said.
It was when he heard the fire sirens, he realised she was serious.
Mayor View firefighter Mel Gearon said Jackson was already out when firefighters arrived because the door had been broken off.
"He got stuck inside the machine and he was after one of the rugby balls," Gearon said.
"He could not get out as the door was opening only one way by the inside. It is quite a little kid and a big machine.
"He was fine when he was out, not even a scratch," Gearon said.
Sheppard said his family was thankful to the fire brigade and Peter Spiers electrical because a couple of their electricians managed to get Jackson out.
"We are lucky as Jackson is very cruisy, he only panicked at the end when the men came (to break the door)," he said. "He started to get a bit frightened of that noise.
Sheppard said he dropped a "couple of dozen" off to the electricians as a thank you.
Sheppard said he had not yet taken Jackson to a rugby game but he was always watching the Chiefs games on the television with him around and thought that would be the team ball he would have been after. "That's the one I'd be after."
In the end, however, all that work was for nothing as Sheppard said Jackson "didn't get the ball at the end" because they were just out of reach.
"It was a bit frustrating for him. I cannot believe he got stuck inside the machine but it will be a good memory for his 21st."
KiwiKrane operations manager Thomas Felton said he would be contacting the franchisee to find out what had happened as the company had procedures in place to ensure children could not crawl into the machines.
He said a similar incident happened overseas about seven years ago and the company introduced blocks to go inside the receiving slots of the vending machines to reduce the amount of space in the slot.
"We have that policy across our cranes," Felton said.
Felton said the blocks, which were painted black, were camouflaged because it was the same colour as the machine. The blocks could have been removed without the franchise owner realising, which was probably the case in this instance, he said.
"They [the blocks] may have been pulled out and not noticed."