Klair would then send invoices, and sometimes debt recovery notices, seeking payment for services people had not agreed to, or had agreed to on the basis of a misrepresentation made to them.
Her scam, which was described by Judge Field as "sophisticated", pulled in more than $719,000 in total.
Field said Klair's offending involved particular planning and preparation and was motivated by "pure greed".
A spokesman for the Commission said the 53 complaints clearly represented only a small percentage of the total number of victims.
It was difficult to know exactly how many people had lost money because some were probably unaware they had and others simply did not complain, the spokesperson said.
Sarah King, who runs a website dedicated to exposing scams in New Zealand, said she had been contacted many times in the past about Klair's false billing practices.
King said the number of people who made complaints was "only the tip of the iceberg".
Many people lost only small amounts of money and so did not bother to come forward, she said.
The Commerce Commission said its case against Klair was the first time it had brought charges under the Crimes Act.
Other prosecutions and penalties previously imposed under the Fair Trading Act had not been strong enough to deter conduct such as Klair's, the regulator said.
Stuart Wallace, the Commission's consumer manager, said businesses should be wary of any unusual invoices.
