Last month I took a survey on tennis. At the end of the survey I was asked to enter my email address and in return, I would receive a $20 Amazon gift certificate. About a week later, e-rewards informed me that they made a mistake in making that offer and credited my account with $10 in e-rewards currency. I complained and they told me they have no Amazon gift certs to give out and credited me with another $10 in e-rewards currency.