Within a few months, one of the straps of the new backpack had torn off. I've never had this happen, so I sent the bag to JanSport, knowing their warranty covers defects.

Anytime I've had issues with a JanSport over the years, I've shipped my bag back to the manufacturer, and they've replaced the product for free.

But, instead of sending me a new bag, it was returned to me with this message: "We are sorry to inform you that your backpack is not an authentic product made by JanSport. It is an imitation and is not covered by our warranty."

At the time, I didn't understand how this could have happened.

Then, I discovered my backpack hadn't been sold to me by Amazon or even JanSport. It was shipped directly to me by a third-party seller.

Many Amazon sales come from third-party sellers, which can be hard to vet

Over 60% of Amazon's sales come from independent third-party sellers. Although this allows the online retailer to offer a greater range of products, it can also be challenging to monitor who's selling them.

An Amazon representative told Business Insider the company has "proactive measures in place to prevent counterfeit products from being listed and continuously monitor[s] our store." But some items, like my bag, fall through the cracks.

When I realized my JanSport was counterfeit, I contacted the seller through Amazon to request a refund. Even though I was well outside the return window, the seller replied the same day.

They told me I could keep the damaged backpack and they'd process my refund immediately. I wasn't surprised I was able to get my money back since Amazon has a zero-tolerance policy on the sale of counterfeit goods.

I now take a few extra precautions when shopping for name-brand items on Amazon













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Now, when I buy name-brand items, I shy away from third-party sellers because it's harder to guarantee a product will be 100% authentic.

Next time I plan to buy something on Amazon, I'll check who's selling it. I can do this by looking under the "Buy Now" button on each listing.

In the future, I'll also spend a few extra minutes checking the ratings of any seller I'm thinking of ordering from. Sellers with only a few reviews, many one-star reviews, or comments that mention fake items, defective products, or lots of lost packages are all red flags to me.

Lastly, buyers can also report counterfeit products to Amazon Customer Service.

An Amazon representative told BI, "If you received a product from a third-party seller that you don't believe is authentic, we recommend customers contact the customer support team for a full refund of the order, stop using an item immediately, and dispose of it."