A Montreal woman says she experienced an unusual form of tech fraud when thieves made off with more than $500 in gift card currency.

After Samantha Vandzura's son was born, her boss gave her 550 dollars’ worth of Walmart gift cards to buy baby supplies.

She went to Walmart and loaded up, but when she got to the cash, she was stunned.

"When I went to swipe the cards, there was nothing left on them,” Vandzura said.

Walmart told Vandzura the cards had been used at 2 different stores in Ontario. But at the time of the purchases, Vandzura was on holiday in Florida.

“They told me there was nothing they can do and that Walmart's policy is not to issue any refunds [and] that the best they can do is give me a phone to call to reach the gift card department at Walmart and print me out this receipt,” she explained.

Furious, Vandzura started doing research and found she wasn't the only person this happened to.

Here's how it works: the card is out in the open at the store - the would-be thief takes the number, removes the strip on the back to get the security code, and uses a replacement strip bought online to again cover the codes

Once the altered card is bought and loaded with cash, the thief gets an alert and spends the money.

“They can exploit the card and drain it before the actual user even uses it,” explained cybersecurity expert Steve Waterhouse.

The RCMP is aware of this type of fraud, but can't say how widespread it is in Canada.

But the Retail Council says in Quebec alone-- last holiday season - consumers spent $245 million on gift cards.

Experts say one way to cut down on this type of fraud is to use extra packaging on gift cards, or simply keep them behind the cash register.

One thing cybersecurity experts caution: don't expect police to spend much time investigating these types of crimes.

“The magic number for me - I was told once was by police services - was $5000 dollars,” Waterhouse said. “Below that it's just background noise, because there's so much of them happening.” 

In Vandzura's case, after contacting the media, Walmart did refund her. However, she says her days of buying expensive gift cards are over.