What have you bought that hasn't turned out as expected? For example, I recently bought a roast chicken from Woolworths for a simple lunch. I tucked into a wing, and then another, and then pulled out … a third wing! The chicken didn't have three wings; a third wing somehow got into the bag.
Five plus years ago, I bought two fakes on eBay and it was a hassle/not possible to get a refund or replacement when it broke down (and the replacement was a fake) or when I found out after purchase - a fake Magnetix toy sold by an Aussie seller and an SD card sold by a Chinese/Hong Kong seller (I learnt this lesson very quickly so I won't hand in my OZB badge). The pendulum has probably swung the other way now for buyers.
Many moons ago, i bought a dud doorbell from Aliexpress. Now I won't buy any electronics from Aliexpress unless someone here has had good experience with the seller.