Wallace claimed the corporate carparking structure on Princes Wharf with the administrative company was "rather confusing", comprising leases for the apartments and licences for the carparks and associated storage lockers.
She admitted she did not tell the Burts she had an issue with the carparking administrator and believed it was only an administrative issue - but that she had paid $80,000 for the carpark and had never sold it.
Wallace believed she had a valid licence to occupy it. However, the tribunal advised that the administrative company said she had swapped carpark 12 - which she sold to the Burts - for another carpark.
After their dealings with the agent, the Burts told the tribunal they felt Wallace single-handedly tarnished forever their feelings about New Zealand, its business community and ethical standpoint.
Wallace failed to return the Burts' $25,000 carpark deposit, the tribunal said. The title to the carpark was disputed, but she did not tell the Burts that when they agreed to buy it from her.
A second complainant, winemaker and vineyard owner David Hoskins, described how a $4 million deal to sell his property to a Chinese buyer via Wallace went wrong and he had spent about $65,000 on litigation.
He described pressure from Wallace who threatened the buyer would "go down the road and buy elsewhere" if an amended agreement was not signed. Wallace then issued a statutory demand for $67,500 commission on the failed deal.
Another complainant told the tribunal Wallace said she worked for New Zealand Properties International and had worked at Bayleys.
The tribunal considered banning her permanently by cancelling her licence, but instead decided on the 18-month suspension, backdated to June 18.
The tribunal heard Wallace, as vendor, entered into a sale and purchase agreement with the Burts for the Quay St carpark. She obtained a $25,000 deposit in October 2007 and part payment of the settlement balance.
Wallace claimed she owned the carpark and had paid $80,000 for it, but failed to tell the Burts her title was disputed. The tribunal said this failure to inform the buyers was misconduct.
In her evidence, Wallace said she did not tell the Burts she had an issue with the carpark administrator as she believed it was only an administrative issue which could be easily sorted.
Wallace could not be contacted for comment.