It seems that the Flash Rewards offering a Shein $500n gift card is a scam. They have promotional deals that you complete in order to get a gift card. The scam is, they say you must complete X number of deals in a specified timeframe (ie 20 days). It's fast to complete deals, but they don't credit you right away. It may take a week or more to get credited. And, you can't complete another deal until you're credited for the first one. This makes it literally impossible to complete all the required deals in the specified timeframe. There are many fake reviews on TrustPilot and a lot of fake Facebook pages. It seems they pay people to leave positive reviews. I was wary when they asked for a copy of my government-issued ID, and collected a ton of personal information.