After braving strong demand for few days, Lumia 521 has again sold out at HSN. This is twice in a row now. HSN was admitted having a much larger stock this time and they termed Lumia 521 as Show Stopper because of huge customer interest. Sadly, this makes the device unavailable in US for now. It is already out of stock at Walmart online and in stores as well.

Lumia 521 link

Thanks hiepsfinance for the Tip. Cheers!!