But now after a three-year battle, the documents have been changed, reversing the cost assessor's mistake and leaving Harris to pay $7800.
Bond told Open Justice the firm was regularly in contact with Harris and sent monthly invoices, which all correctly stated the GST position.
"She never raised an issue with our fees but then at the end, she complained that our fees were too high."
After the complaint, the pair took the issue to the Law Society where it was ruled the fees were fair and reasonable.
"This is where the cost assessor mistakenly used the word 'including' instead of 'excluding' when referring to GST and disbursements."
Bond said the mistake was acknowledged and would be corrected if the client consented, but Harris refused.
"She argued she no longer had to pay the full amount she knew she owed."
After learning of the cost assessor's mistake, Braun and Bond invited the Lawyers Standards Committee to change the error.
But after several months of deliberations, the Legal Complaints Review Officer [LCRO] declined the application on the grounds that it was an "abuse of process".
Bond and Braun said the LCRO did not give them any warning of the intention to strike out the review application or the finding that they had engaged in an "abuse of process".
In her decision released last week, Justice Christine Gordon granted the right to change the legal documents and ordered the committee to change its decision from August 17, 2021 to state that the invoices excluded GST and disbursements.
Justice Gordon's decision said the lawyers should have been given notice of the outcome the LCRO was considering and given the opportunity to respond.
"The LCRO's failure to do so was a breach of natural justice," Gordon said.
At the High Court deliberations last month, Harris told the court she did not say she refused to consent.
"I just didn't respond to the letter from the committee."
Open Justice attempted to contact Harris but she did not respond.