I just spent 20 minutes completing a 9 minute survey.
I wouldn'ty have minded that but after finishing I got a screen saying thank you for completing this survey followed by another one saying sorry you did qualify for this survey.

This is the second time this has happened to me.
Has anyone else had this problem?

Yes it happens.

Mostly it is due to a pre-screener. You think u r taking the survey but actually it
is a pre-screener to see if u qualify for the survey.