She left the laptop in the care of her 11-year-old daughter.
"Nothing was coming up, so she decided to have a look and see if she could get tickets elsewhere.
"She typed in Ed Sheeran tickets and the Viagogo website popped up at the top of the list," said Harper.
Viagogo is an online ticket marketplace for buying and selling tickets to live events.
"All of my details came up pre-existing in the computer as soon as she put my name in. She sort of assumed it was all good."
Long story short, she ended up with three tickets for $1223, which should have only cost $90 each, she said.
The money came out of her bank account immediately.
Harper said her bank could not stop the transaction, so she made a number of phone calls and emails to the Viagogo website, asking for her money back.
"Viagogo emailed back saying the only way to get my money back was to re-list the tickets on their site and sell them again.
"That's appalling. It's really awful.
"If you tell them it's an 11-year-old child and they've made a mistake, there should be some comeback on this."
Harper said her daughter was distraught.
"She thought she was helping. She thought I'd be so excited.
"But when I saw what had happened, I thought, oh no.
"The moral of the story is, don't leave your daughter with the laptop."
The Major Events Management Act 2007 makes it illegal to on-sell a tournament ticket for profit in New Zealand, and scalpers can be fined up to $5000.
However, it is restricted to major international events, such as the Rugby World Cup or Cricket World Cup.
The re-selling or scalping of tickets to concerts, entertainment events or one-off matches is a legal practice.
