There is a paper: https://a16zcrypto.com/posts/article/new-paper-alert-fair-data-exchange/.
Read it, understand it, see whether we can apply it/modify it.
It does not need to be this paper, but basically we need a way to incentivize storage providers not only to create proofs, but also to send the data back to the customers. Currently it's on we trust that they will basis.