Backing a Kickstarter project is giving money to the project owner to help him realize his project, not buying a product, there is no buyer protection.

The perk announced for the backers is a reward for their gift. There is no obligation for the project owner to give the perk to the backers nor to refund the money, even if the project is successful (and for Helix, since the project was about producing a titanium frame folding bike for much less than anybody else, since it was proven that it wasn't possible to produce Helix at the price announced in the Kickstarter campaign, its possible to claim that the project failed to justify that all backers didn't receive their perk even if Helix was eventually produced).

Unless it can be proven that the project is fraudulent (for instance that the project owner didn't really tried to realize his project and just took the money), backers cannot complain if they do not receive any perk.

Pre-orders are different, its a sale, with all buyers protection like for anybody buying any product online.