Sounds like US isn't only bankrupt in a financial sense

Ask for a Sup and if they give you the same cock & bull then tell THEM to call OS and verify it for themselves. Sheesh!.

Another way is to get them to look at the profile for a * RTW ticket, check the invalid fliight numbers for OS, compared to the flights you are interested in, and voila, the penny may just drop....

Good luck!