I don't know if this is the case for CF but it seems to be for other businesses.
I don't think it's usually that they don't know what's going on, but that they don't want to tell you, because they think that's giving away too many details.
I've been flagged in many systems as I move around in the world quite a bit, so sometimes I use a credit card acquired in one country in another, and a couple of days later using it on the other side of the planet, which triggers their anti-fraud systems. Then I write to them and they reply something like "Unfortunately you cannot continue to use our services as your account been flagged as potential fraudulent use. We cannot give you any details because then it'll be easier for fraudulent actors to work around it, so I'm sorry we cannot tell you anything else. Bye."
This is why these types of complaints need to be cc:'ed to your congressional representatives in the US or EU representatives elsewhere. No one else can do anything about the root problem of companies that take customers' money and deny any form of accountability.
For every customer who gets lucky on Twitter or HN, there are probably a dozen who end up with no recourse at all.