International SMS stops working

Does anyone have a suggestion as to what to do when, from one day to the
next. SMS messages to a specific overseas location cease to work, in either
direction? I know, call Cingular... Then you go through the imbecility of
having to waste your time working up the line - first, a rep who wants to
know if you know how to turn your phone on, then finally, level one tech,
not much better ("The problem is certainly at the overseas location"), then,
during my last experience, after alot of nonsense ("There's really nothing
we can do..."), they admit that they can pass you along to level 2 technical
support. In my last experience, after 4 tries, well, they would have to call
me right back because "the boss" was in a meeting. Then these sob's (excluse
me) just blow it off and don't call. Making you go back to the whole process
again.

Does anyone know WHAT the technical capability of Cingular is to trace an
SMS and determine WHERE a problem is occurring?

I have even less luck at the opposite end, Russia, because their notion of
customer service is even worse.

The word there from the local mobile provider was, "We don't have and never
have had any contract with such a company in the US [i.e., Cingular]."

This is, of course, pure nonsense. SMS to and from a number at that company
has worked (since the last problem of this type) for well over a year,
pretty much flawlessly. And when I was there (Siberia), I roamed in that
network with a Cingular SIM in my phone.

Any advice?

Thanks!