"I feel pretty gutted. I was pretty excited to play a show after a whole year of not being able to play to anybody to share a bit of new music with people," he said.
"It's upsetting and for us it's the only way we were able to make some income this year, and it's a little troubling."
After a year in the recording studio, they had been due to play live at Wellington's Downtown Shakedown Festival early next month - to a sold out crowd.
The voucher system had not even gone live when Georgia's flights were booked three months ago.
Caleb said the airline, Air New Zealand, advised them it had emailed the information in September - but Georgia said she did not receive it.
They later learned about the voucher system from their mother, who saw an ad on television and called them - but by then it was too late.
"When they brought in the voucher I think the most logical system would be to look up who had already booked their flights and maybe grant them the spots first before the vouchers booked up," Nott said.
In an email seen by RNZ, government officials warned there could be "a bit of backlash in the media about this" given the duo's profile.
In another email, head of managed isolation Joe Stockman said thousands of people with existing bookings secured vouchers in the first hours after the system went live.
"This was heavily advertised, and we're confident that the rules were clear," Stockman said in the email.
"There is no exception for people who booked their flights before the system was put in place, and there is no mechanism we could have used to auto give them vouchers (we don't know about them unfortunately)."
Broods are not alone.
Others who booked flights home before the voucher system went live have contacted RNZ, concerned they cannot secure a place in managed isolation to match their flights.
Speaking from her home in London, 80-year-old Eliza Beverage said she would not make it to spend Christmas with family in New Zealand as planned, despite booking her December flight in June.
She did not know about the voucher system.
"I could have arrived at the airport with all my luggage and they would have turned me away, said 'sorry you haven't got your voucher'. If she hadn't called me I wouldn't have known because I don't know what's happening in New Zealand."
She was due to visit her daughter Candida Beverage, who also learned about the voucher booking system too late.
Candida has taken her mother's plight to the ombudsman.
"Why is it that people who bought tickets at the beginning of the year to come back to NZ before Christmas are not the first people receiving vouchers? Surely they deserve to get a voucher first, and they should be sent a voucher," she said.
Another New Zealander living in the UK, Joshua Denize, is returning to live here in January but cannot book vouchers to match his family's flights.
"At that time 15th of Jan was the very latest on the calendar within the managed isolation system that you could book. I assumed that was possibly because it was a sliding window and that would change but it never did. It's rather frustrating."
After contacting four press secretaries, RNZ was advised Chris Hipkins would not be available for comment today - the day he has been officially sworn in as Covid-19 Response Minister.
Air New Zealand said it had been advising customers about the need to have a voucher to board a plane to this country, and referred RNZ's request to MBIE.
In a statement, a spokesperson for MIQ said that because they relied on airlines to provide flights details, they were limited in how far out we can upload this information to the system.
"We are continuing to load flight data once we are confident of its reliability," the spokesperson said.
"An extensive awareness campaign has been under way since September. This has resulted in people from 212 different countries accessing our Managed Isolation Allocation System website. We've done everything possible to ensure those travelling knew they needed to book a space in managed isolation and airlines have also been providing this information to their passengers.
"A key constraint on adding new facilities is the essential workforce who care for returnees. We need nurses, defence personnel and police to run these facilities, and this a limited workforce.
"We currently have a spike in the number of people in managed isolation facilities and there is very limited availability for the rest of the year."
Prime Minister Jacinda Ardern said there had been plenty of warning about the voucher booking system being compulsory from 3 November.
"We have long signalled the need for people to have a place within MIQ, that's been part of our public communication for some time because we need to make sure we can manage the flow of New Zealanders and the high demand we have before Christmas."
She said there had been difficulties for people using third-party booking sites and they were relying on airlines to communicate travel conditions.
"We have no way of knowing who has booked a flight and when they have booked it. That is a relationship directly between an individual and an airline and sometimes even involves a third-party booking system. That is why we flagged in advance the need for people who will be entering New Zealand from that date to have a voucher."
As for Broods, they are among many facing a Christmas apart due to the pandemic.
Caleb Nott said it would be the first time he and his sister had been separated for the season, but they did not want special treatment.
"It will be the first time she hasn't been at Christmas. It will be a hard day for her if that ends up being the situation but also we don't want to be in a position where G gets a spot and thousands of other people don't, because that would be totally unfair."
He wanted the government to admit it had made a mistake and acknowledge those who missed out on vouchers despite having flights home.
-RNZ
