Piracy and fraud kind of just comes with the territory especially in the realm of digital merchandise. It's kind of just one of those things that you need to learn to accept unless you want to go down the DRM route (and even then no game is truly safe, because even the strongest DRM can be cracked). Regardless, even if someone WAS account sharing, unless they flat out admitted to it there is nothing you or the administrators can do about it as there is no limit on the amount of times a game is allowed to be downloaded in the ToS and there is no way for you to know for sure what their real reason for doing so is. No way for you or the administrators to know whether or not someone is account sharing or if they legitimately have 10+ devices they wanted to download it to or if they just for some reason wanted to download it 10+ times or were simply having a connectivity issue and the downloads were getting corrupted or if it's just an error with the counter itself. You having a suspicion about it simply is not enough justification for you to do anything about it. I understand why you might be concerned, but the reality of the situation is that it's just something you're going to have to learn to accept if you wish to continue to make and release games.