1. Plenty of times when I'm filling out surveys, the advertised time of the survey changes.
For example, a survey might be listed as 90 credits for 10 minutes. But after you click the link, it sends you to a 20 minute survey.
There should be a quick way to report such time inconsistencies. The survey people get away with it because people will still do the survey if the time changes, as they already clicked.
2. Also, other times when I'm filling out surveys, I know that I've completed the entire survey (spending 10-20 minutes or so). But the last few questions are demographics questions that disqualify you, after you've completed the entire survey. So the survey people have your data but don't give you the credit.
Most surveys have the demographics questions at the beginning and disqualify you before they waste your time. There should be a quick way to report that a survey made you fill out the entire thing but disqualified you at the very end.