I dont normally leave one star reviews; however, the lack of response from this developers support email is what pushed me over the edge. I will happily revise my review and rating if the developer would simply reply to the support email address listed right in the app. I installed this app on the recommendation of a major, reputable media source reviewing several similar apps. After installing it, I discovered that in order to handle more than 10 contacts, one must upgrade to the pro version for $2.99. With only a brief hesitation, I went ahead and paid the upgrade, based on the review I have read. Unfortunately, the product does not work, because the app cannot handle more than apparently 2000 or so records without crashing. The app indicates I have over 14,000 contacts, which seems vastly inflated, even though I do have perhaps 100 or two duplicates that appeared during a recent restore of my phone. Perhaps it is counting each individual phone number and email address within each contact as a different record. In any case, when I try to back up my contacts, it gets to about 2000 of the 14,000 and then the app simply quits. If I try to process a merge without backing up, and tries to back up anyway and still crashes. I emailed the developer at the support address displayed in the app itself offering to provide anything I could to help diagnose the problem, including logs or anything else, and its been a week now without any acknowledgment of my email. I now see several other reviews of this app mentioning the same problems Ive experienced. I wouldve been more optimistic about the problem being fixed and would not have left a negative review have the developer simply responded to my email. However, his nonresponsiveness does not give me hope that this problem will be fixed anytime soon. As such, I feel I must leave a one star review, because the app is too buggy and simply cannot do what I paid for it to do. Again, if the developer is listening to these reviews and would like his score to improve, all he needs to do is reply to my email.