Small claims court. Sue them for damages (and punitive, if small claim courts allow).
Also, report Rumblefish for sending fake DMCA requests, it's illegal.
Also, report Rumblefish for sending fake DMCA requests, it's illegal.
If it's the latter, then I believe that makes Rumblefish guilty of copyright infringement, since they're profiting off the copyright (the video) of the poster.
DMCA request or not, that seems like it would be actionable.