Another survey host to avoid on e-rewards is opinionbar.com. I've now had three surveys in the past year concerning family finances from them. Around 89% of the way into every survey they ask about the credit cards you have and which ones are co-branded. There are columns for each brand of credit card and it asks which type of co-brand each card is affiliated with (hotel, airline, gas etc.) No matter what you answer, it will then say "Please select at least one per column" and will not allow you to go any further.

I've written opinionbar.com with no response, and now waiting for e-rewards to reply. I seriously doubt that it's an ongoing coincidence that you have almost completed the survey and provided all that information when the path to completion is blocked.