No, dTuble is not defect. Your videos did not get enough upvotes and with it not enough payout:

dTube does not seed. They use IPFS for storage. And that IPFS storage isn't free. You get 7 days sponsored and then you pay with 25% of the money you made with the upvotes.

Sadly I have to conclude that @dTube not suitable for long term storage. At least not for small channels which won't get a reliable amount of upvotes on any video.