Sounds to me like you aren't targeting your campaigns properly and which sites they appear on. You could show a hamburger ad to 55,000 vegetarians and you wouldn't sell one hamburger.
Also, think about your ads. If you are delivering that amount of clicks an no sales, maybe you should change your ad to something that isn't so general with such a high blow through CTR. A high CTR only works when the content they end up on can convert. It might sound weirrd, but try toning your ad down so that you can get a lower CTR rate but a higher conversion rate by getting real interested buyers.
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