everifier.org Extention Problem

I have purchased everifier.org extension, previously it worked fine but now is not varying email when I import CSV list.
I have checked all setting but I didn't find any solution. Admin, can you please give us a solution?
Are you absolutely sure your extension is enabled in backend and also in customer area and the customer has added proper api keys and selected proper check zones?
It is usually better to do address verification as a standalone op, and then go with the clear results. You can later gently try some of the questionable results, and once that is all done (but very carefully for various reasons), then you can check out some of the rather bad results, if at all need be, but best is to only use the clearly good ones ;)