I have successfully invited two friends and claimed the related rewards after following the link the first time I received the notification. However, your system keeps emailing me to claim these rewards with the same content and link. My email is flooded with these notifications, i.e., 30 emails within an hour, and it keeps sending again the next day or two. I have no unsubscribe option for these emails. It's quite annoying. I hope you can fix this.