TrustRadius Denied My Gift Card After I Reviewed a Product I Know Well

TrustRadius emailed me requesting me to review a product I know really well, and in exchange they promised a gift card. I reasoned why not? I really took some time to carefully and honestly write a review. I get another email a week later stating I obviously lack the "necessary knowledge," so I will not be getting the gift card. Obviously? If I hadn't known the product from inside out, I wouldn't have bothered at all. They seemed to be looking for free stuff, never meant to send anything. I'm very ashamed since I fell for that. TrustRadius seems far from reliable or genuine based on this encounter. Surely wouldn't advise spending your time like I did.