Project Creators are required to fulfill all rewards of their successful fundraising campaigns or refund any Backer whose reward they do not or cannot fulfill.
If it does not fully fund, you receive a refund from Kickstarter.
If it does, your funds go to the project, who are on their best effort to successfully launch the project.
You are NOT, however, directly purchasing a reward. You receive a reward as a gift for helping to fund at a given level.
But you ignore the bigger problem. How are you, as a Backer, able to require a refund because a Project breached its terms with Kickstarter?