And there's the point that makes fixing this stuff such a bitch: you almost
never have a relationship with anyone except the carrier you connect through
(and sometimes not even them :-).
This is, incidentally, why my professional recommendation to people setting
up "nailed up" links over the Internet is to move heaven and earth to
get every point on the same carrier, or to make sure, at the very least
that there is only one exchange point in the middle, and you're a customer
of the carrier on both sides of it.
Having to escalate through 3 or 4 carriers to get something fixed isn't
just time consuming, it's often impossible.
Social engineering NOC hotlines (as much as I hate to advocate it) is
often the only solution; bring your Geek License.
Cheers,
-- jra