Wow, I would say that you are actually lucky that you only got a 15 streak, since some people had streaks of 30+ losses at justdice. Dooglus made a post about it somewhere, and that was a few years ago. You should read the thread about whether martingale works in the long run or not - There are some pretty good posts about this. Like the first reply said, a 15 streak isn't that unlikely.