Good Samaritan Jeff Kelsall gave a stranger a roof over her head and she repaid by not only leaving with his laptop but using his credit card to splurge more than $700 online.
The Kaikohe road worker believes the woman, in her early 20s, colluded with others and even had the audacity to order their shopping to be delivered to specific addresses in town.
The address of a house in Whangārei was also provided.
It wasn't until Kelsall logged in to pay his bills that he discovered $740 had been spent using his credit card, including a latest PlayStation and accessories from Amazon worth $714.
Despite contacting his bank to cancel the credit card, he discovered another purchase of $US146 ($217) had been made for three pairs of shoes from AliExpress. He was able to cancel that order.
When he came home for lunch on earlier this month Kelsall discovered two laptops missing and reported the matter to Kaikohe police.
"The annoying thing is I've worked as a Corrections Officer for nine and a half years and I am used to dealing with idiots but I got sucked in," he said.
Kelsall said a friend asked him to help the woman who needed a place to stay nearly three months ago.
He lent her a room and his laptop for her to watch movies and when she moved out, she took the electronic device with her.
Kelsall managed to get it back but didn't know about the mystery online shopping using his credit card details until he sat down to pay his bills.
"I am gutted because I try and help people in need and they turn around and rip you off. It's really disappointing."
Kelsall said his bank would refund him the money fraudulently used from his old credit card but said it should never have come to that.
He is urging people to ensure their passwords on all electronic devices are protected at all times, even when they are lying around the house.
"Do not put personal information that's easily accessible and be mindful of who you let use your cellphones and computers because you never know who you can trust," he said.
Police confirmed a report has been lodged and the matter was being investigated.