I am not sure if you mean that you are getting to the point where it says there are no more surveys and then you try again later in the day or you are just trying over and over until you qualify in the same session. If you are going into a new session entirely, you should clear your cookies before doing so. It would not hurt to clear your cache too if you can. This should help you to earn credit. I guess too if this does not work and if you do not qualify the first time, then just try again the next day. No point in spinning your wheels for nothing.