That's the thing with luck... You could increase your chances, but not the results. Ie you may have a 99% chance of winning (buy 99 tickets from a lottery of 100 tickets), and yet you can lose, TWICE

Throw a coin, should be 50/50 right? actually there is a 2% chance it lands standing. What are the chances of the next throw to make it land standing again? 2%. Very unlikely but possible.
In theory it should approach 100%. Another possible reason for bad luck could be misbehaving mining equipment or rentals, not sure what the exact issue is why some pools do ban some gear.