Japan dispatching work: has the law changed?

This one comes up in the context of my visa renewal.

I had thought that I’d registered with a dispatch agency who shall remain nameless. (And no, it’s not Interac, it’s another one.)

As I understand the labor law in Japan, the dispatch company first hires you. Then, they dispatch you out to a client company. I have worked dispatch before, and this is what I understood.

In August, I signed up with a company who took my bank account information, copies of passport and ARC, and had me sign a confidentiality statement.

Now, I’m being told I am not an employee of that dispatch company. Even though they took the bank information and had me sign a confidentiality statement.

Which is it? I don’t think dispatch is the kind of thing where the dispatch company hires you only when they find a client for an assignment, (or fires you when the job ends.) Has something changed?

This is really just one more headache, because it looks like I’m blowing hot air, when the unnamed company in fact looks like it’s doing something that’s technically not right . . .