If you're having technical problems with the binary cache as a user, @Austin Seipp is a Fastly engineer, NixOS developer, and @Graham Christensen is a major developer and operates the cache configuration. Please reach out on IRC to @thoughtpolice or @gchristiansen for the speediest response, but email also works for lower priority issues (and higher latency.)
Bugs/reports submitted to us will be diagnosed, fixed, or reported in the bug tracker, or some mix of the three in some undetermined order.
@Austin Seipp can be contacted for high-priority technical or operational issues regarding the cache. But you may want to consider filing a support ticket if the problems are big:
Submitting Fastly support tickets
Questions regarding Fastly's Open Source Sponsorship program, of which nixos.org is a member, should be directed to Elaine Greenberg. (This should only be relevant for The Stichting NixOS Foundation, as well as @Graham Christensen.)
Fastly runs Beta and Limited Availability (LA) project programs for certain customers. For enrolling in those projects, please contact @Austin Seipp and Elaine, so we can see what we can do.