There is zero legit project out there that provides a guarantee. There are companies out there that have secured some of their funds and thus can offer some money back guarantee, but not 100%. Anywhere you invest, they will always tell you to only invest as much as you can afford or that never invest what you can't afford to lose. This is very reason why basic scam websites use the term "100% money back guarantee" or something. They want their investors to have assurance and be confident on investing to them. Once they have ran away, you have nothing left to do but accept the fact that you got scammed.
Seriously, how can a company that have lost money give you back your money? They've already lost it (assuming that the project failed).