Redis is an open source project. There is documentation and links to source code available at
redis.io . The bug tracker and source code are:
https://github.com/antirez/redis . You can ask your question in this mailing list, or you can ask your question on Reddit:
https://www.reddit.com/r/redis or even Stack Overflow.
If you are interested in commercial support, there is no real "official" commercial support for Redis, though I am sure there are several companies and individuals who offer such services, beyond the known hosting providers available.
- Josiah