Email them and tell them exactly what happened. They need to get feedback to weed out survey companies that are apparently trying to get information for next to nothing.

Last year I spent 25 minutes answering detailed questions about a specific medication, only to reach the demographic questions at the very end where I was rejected with "sorry, we have enough responses from your group. Here's your .25 cents." I was spitting mad when I emailed E-rewards, and they not only credited me with the full amount, but said they would look into this survey company's practises.

Sometimes it pays to complain.