Scammers working thru Walmart online ordering?

I recently ordered a $50 item thru the Walmart website. It was cheaper than normal price, but I figured that it was safe since it was thru Walmart. Today, it was shown to be delivered by both the Walmart tracker and the USPS. However, I received nothing. Walmart confirmed they had my correct address, but when I went to the USPS office with the tracking number...they said it was to a completely different address. I looked at the seller's feedback and there were similar issues of non-deliveries. It it matters, the seller is in China. How does this scam(?) work?