But she assessed the grievance about wages.
She made her decision after a meeting with Mr Singh, Joti Jain and Rajwinder Grewal.
Grewal took over from Jain as sole director of NZ Tradings in August this year.
Ms Campbell said the parties' accounts of what happened differed in "many significant" respects.
Her decision also said some of Mr Singh's claims for outstanding pay amounted to "speculative guesswork".
Mr Singh started working at Masala Browns Bay in May last year and left just before last Christmas.
Ms Campbell ordered the company to pay Mr Singh $4572.50 in unpaid wages and $1018.03 for unpaid holidays. She also ordered it to reimburse the $71.56 fee for lodging a complaint with the authority.
On Friday Jain was sentenced at Auckland District Court to 11 months' home detention and 220 hours' community work after earlier pleading guilty to 15 charges.
Grewal was given four-and-a-half months' home detention after admitting five charges.
Jain was the main target of a Ministry of Business Innovation and Employment sting which found that, between 2009 and 2014, she significantly underpaid four employees and strung them along with the promise of letters which would help them obtain a visa.
She was told to pay $56,719 to cover the underpayment. Grewal was ordered to pay $4781.
The saga has affected unrelated restaurants.
Mint, in Titirangi, is on the site of the Masala outlet that used to operate in the village. However, a spokesman said Mint had bought the business and it has never been part of the Masala group. It has a different owner and is unconnected to the chain.