Reyth makes a great question. Did you observe or bet on each one of 15K spins?
The definition of a winning system is a reason for too many misunderstandings. Everyone's expectations are different and many expect the impossible. If you can almost (there's never 100%) consistently, on average, make $10 profit in under an hour with less than 1K bankroll, then you definitely have a winner there. Even if you can make $10 within 2 hours with 2K bankroll you have a great system. Because this means that if you increase both your bankroll and playtime you can exponentially increase your profit, playing more time with higher value chips.
Where do you play? Online, B&R casino, airball etc.?
Do you play with real money?
There is always a sequence from hell. Neither you nor anyone else can avoid this. You don't have to search past spins to find it. Just write down the numbers that would make you lose
bet after bet. Then look at this sequence and ask yourself does this look impossible? Chances are that it wouldn't look too strange to dismiss it as impossible.
This however does not mean that all systems are useless. What this means that there is always the chance to go bust! Like there is always the chance for something totally unusual to happen in our lifes, like winning the lottery. There is always a theoretical chance. The reality is that most people don't win the lottery. It's the same with a great system. there is always the chance to go bust, even if you had the best system ever. A good system can minimize the chances to go bust but can't prevent it with absolute certainty.