yougov.comは安全ですか？

I have been a member for a few years, I have redeemed 2 restaurant cards, but i thought i would save enough points for the large prize. After getting the required number of points, almost a years worth of surveys, i submitted the points for the $100.00 Visa card. It stated 4 - 6 weeks. It has now been almost 4 months, still no card. All correspondence to YouGov has gone unanswered. I have left messages on Twitter, Facebook, and still no reply from YouGov. I did receive replies from several others who have experienced the same problem. Google searches have revealed even more people who never received their cards. Do Not Trust YouGov to fulfill their obligations.