Mayoral aspirant Leo Molloy, who pulled out of the race this month, said he had planned to spend $1.5m on his campaign.
A week ago the Herald reported Beck had been locked out of her original social media and website accounts after a failure to pay for work that included setting up an online presence.
In the wake of that story, backers played it down with C&R board member Nicholas Albrecht - who is a member of Beck's campaign team - saying negotiations were continuing but "a good two-thirds has been paid".
The claim prompted an email to Viv Beck by Matt Blomfield, whose legal services agency was hired to recover the outstanding bill for advertising agency Hello Ltd.
In the email, he told Beck: "The statement is not true, Hello Limited has not received one cent from you or any associated organisation as payment against its outstanding invoices."
In it, Blomfield said he had reviewed the invoices and emails exchanged with Beck and her team. In his email, he claimed "donations did not arrive as expected", leading to the budget being scaled down from $4m to $2.2m and "as an excuse not to pay … the invoices from Hello Limited became an issue".
Blomfield said his review of the correspondence between the agency and Beck's campaign showed Beck had not raised any issues in relation to the quality of the work done.
In a statement to the Herald, Beck said Hello Limited was introduced to the campaign team in early 2022 and a broad scope of work was discussed. No formal agreement or contract was entered into by parties, she said.
"Hello subsequently invoiced the campaign for work undertaken that, according to industry sources, was excessively priced and did not meet the needs of the campaign as discussed with Hello," Beck said.
She said she was "extremely disappointed" the issue had been made public when work had been underway to resolve the dispute.
"This is a complex matter and my team has acted in good faith on presenting what I believe is a fair and reasonable settlement offer, which was presented some weeks ago."
"There will be no further comment as parties endeavour to resolve this matter," said the mayoral contender.
A spokesman for Hello Limited's James Polhill confirmed settlement talks had been held. He said Polhill's representatives withdrew from those talks on Saturday at midday after failing to reach a settlement.
The spokesman said it was expected the total amount owed would be paid and that Beck had never questioned the amount owing.
The Herald was told the invoices for the work were sent on February 28, March 31 and April 30 and totalled $353,504.25. The invoices detailed a broad range of tasks across months from setting up office systems for the mayoral campaign, contracting photographic and video work, creating brand strategies, an online presence and designing online and other advertising work.
Blomfield said the assurances given to Beck's backers - including C&R president Kit Parkinson - suggested "someone within your team" was trying to "mitigate some of the damage" from the unpaid bill.
The email from Blomfield to Beck set out the awkward situations he claimed were created by the debt recovery task.
Those included the presence of Andrew Krukziener as one of Beck's donors and also "a very dear friend" of Blomfield's. The email also noted the family links between Hello Ltd's managing director James Polhill, his wife Gilda Kirkpatrick, and Krukziener, who was married to Kirkpatrick's sister Gitta.
Blomfield said links to Krukziener had held him back from encouraging Polhill to respond publicly or to take further steps to recover the debt but claims most of the debt had been paid had led to an impasse she needs to resolve.
"It is your name that was put forward as a candidate for Auckland Mayor."
He wrote that, in his view, Beck "should have taken responsibility for what was happening in your camp, that includes managing budgets and the people working for you".
"This issue with Hello Limited is your issue to fix, nobody else. In the same way I have stood back and watched this unfold without action, it appears that you are counting on relationships that you have to simply sweep this under the mat."
Blomfield wrote that doing so was, in his mind, "not fair on James and his company Hello Limited".
"I am not interested in hearing issues you have with the size of the account ... The time passed for that months ago, these invoices are in some cases over six months old. This is your issue Viv and you need to fix it."
Blomfield told Beck that she had until 4pm on Friday to come up with a "suitable resolution" to the debt or work would begin recovering the money and correcting claims made in the media.
The Herald identified last week that Beck had shifted websites from one registered in February to a new website registered at the end of July. Likewise, her Facebook account had switched from one with posting back in March to one created in the last month.
Five days ago, two senior members of Communities and Residents were adamant most of the bill had been paid.
C&R president Kit Parkinson said there was nothing to the advertising bill, saying he had just found out there was a small issue way back but it was settled and everyone was happy.
"I know there was a business transaction that went on, I know the business transaction was settled," Parkinson said.
It was Parkinson's opinion that "this is a pure beat-up by one of the other competitors in the [mayoral] race".
He referred the Herald to another C&R board member and a member of Beck's campaign team, Nicholas Albrecht, as the person who knows the "ins and outs".
Albrecht said the bill was no "big issue" and most of it had been paid.
Asked how much was left to pay, he said negotiations were continuing but he believed "a good two-thirds has been paid" in the last couple of weeks, but was not 100 per cent sure of that.
He referred the Herald to property developer Andrew Krukziener - donor to Beck's campaign and brother-in-law to Polhill, was overseeing the bill.
"When are you going to do a hit job on some others," Albrecht said.
The Herald is seeking comment today from Parkinson and Albrecht.
Viv Beck was chief executive of central Auckland promotional vehicle Heart of the City until she entered the race for Auckland Mayor in March. She did so on a pro-business, centre-right platform, and secured support from right-leaning C&R.
Beck echoed National leader Chris Luxon's pledge to scrap the regional fuel tax and seek out different funding sources for infrastructure projects.
Polls have so far seen Beck lagging behind other contenders for Mayor. The front runners in current polls are Labour-backed Efeso Collins and independent Wayne Brown, the former mayor of the Far North. A large contingent of voters identified as undecided.
Krukziener has been a prominent voice in a campaign opposing Auckland Council's pedestrianisation of the central city. He was among a group of business and property owners who sued the council claiming its plan for Queen St was causing "significant economic harm".