TORONTO -- If you play video games, or have children who do, you know there can be charges if you purchase add-ons for games played on your phone or tablet.

Usually, people would have to provide their billing information, but you should know some games may charge you automatically and bill your credit card without your knowledge.

“I was shocked and I thought I didn't make any of these purchases and I had all these charges on my credit card,” said Laurie Ovenden of Bowmanville, Ont.

Ovenden adores her six-year-old grandson so when he asked to play a free game on her phone she agreed.

She said at no time did she give her grandson her credit card number or enter it into the phone to play the game, but not long after she got a surprise bill from google.

“I got an email messages saying thank you very much for your purchases and receipts. It totalled more than $400," Ovenden said.

Ovenden complained to Google and her credit card company but she was told there would be no refund.

"I said are you going to take any charges off and they said no because it is friendly fraud. I said what's that? They said it's because the charges came from within your household and I said yes but I didn't authorize anything," Ovenden said.

Tech expert Carmi Levy of London, Ont., said unfortunately “this is a very common thing and I hear stories like this all the time."

Levy said if your credit card number has been entered into your phone even once, some apps may be able to find it and bill you even without your knowledge.

"These (your phone) are payment devices and it is shockingly easy for a phone to make purchases without you even seeing" said Levy.

Levy said the best way to protect yourself is to go into settings and disable in-app purchases.

"By turning those off, you then require the phone to ask you do you want to make a purchase? That way you'll get a warning and not a surprise bill," Levy said.

Ovenden changed the settings in her phone, cancelled her credit card and wanted to share her story to warn others.

"It was very upsetting to know that this could happen so easily," Ovenden said.

If you're not sure how to shut off in-app purchases, you can contact your cell phone provider.

It's also another reason to keep a close watch on your bank and credit card statements to check for charges that shouldn't be there.