My first comment is what value is there in .BIZ ...? International names in .COM would seem to make more sense. But that's just my opinion
Arg-
Have you tried registrar transfer outs? That's really the only way to get control of them without lots of hassles.
Another thing to be aware of is that even though many CORE "registrars" became ICANN accredited, many of the domains registered through them back then are still held by CORE; at least the last I checked.
Request registrar transfer out requests, repeatedly say every 7 days or so if necessary, on the domains - many will go through ... eventually
Ron