I agree with rosiesmom. If I get the message that I completed a survey, and then it takes me back to the survey site saying I haven't qualified, I will usually leave a survey site if that happens numerous times.
I'm going to answer your other question. It's 50/50 for me whether I contact a survey company or not. If I contact them, and they work with me, I will stick around. But if it becomes a constant problem, I will leave. I left one site that I really liked because they refused to give me any sort of credit for a survey. Then after writing back to them, they agreed to give me points but never did, which I found really shady and I called them out on it.