I've found a number of them pull this nonsense. They'll say that they only need a certain number of surveys and then the offer is closed and you only get partial credit. Of course, you actually have to fill out the whole thing before you find out they've met their "quota".

The easy-hard solution is to feedback E-Rewards on the matter.

Get the affiliate's link (they'll ask for it later) and point out that there is no excuse for them to do this - some of the offers play it legitimately, and you can't open the offer if it's already met "quota" or whatever other prerequisite. And really, there's no reason they can't - if they have qualifying questions, they should be placing those first. So basically, they're (the affiliate) running you through a 10 minute gamut, wasting your time for $0.25 partial reward and walking away with the data you've provided for them.

Point out in a non-accusatory manner (politeness works wonders) that while the affiliate's are responsible for this behavior since they're the ones doing it, their behavior reflects very badly on E-Rewards as the company is allowing the affiliate to get away with doing it to their customers.

I don't know how this affects their relationship with each specific affiliate, since that's in their park, but I've noticed a difference. More importantly, I got full credit in the two complaints I registered after getting fed up with a pattern of this. The number of available surveys does go down. It's a step towards finally cashing out if you want something back for your time.

Once I get my reward, I'm done with it and will be looking for a better offers program. This one has too many problems (these weren't the only issues I had, just the ones I did feedback on).

The process of getting credit through feedback can be slow, but you're getting more out of it than you do on a survey that cheats you.