I would look at these two bug reports that are open, Uploading Audios indiscriminately gets it removed instantly due to false 'IP Violations' - #10 by complexlint
and Roblox removing songs licensed under Creative Commons Attribution. Currently, what we’ve been told is you cannot appeal this either, because they “don’t have any current way to validate licenses” if it gets flagged by the system.
I personally think this is ridiculous because I’ve found many CC0 SFX, that should have no problem if it wasn’t for an unnecessary block, but it doesn’t seem like there will be a quick fix in the near future for this either.