I am sorry for your experinece again, this is the similar question of yours. https://learn.microsoft.com/en-us/answers/questions/832529/voice-not-found.html?childToView=832691#answer-832691
Some of the voices are in private preview but by mistake the engineering team showed it to public. When they found the bug, they rerolled the release. I am sorry about that, the engineering team will target releasing it on May 9th, please stay tuned.
This is a simialr issue: https://learn.microsoft.com/en-us/answers/questions/815091/index.html
In the future, the engineering team will avoid same issue happens again, they will not delete any existing voice unless officially announced deprecation. Please let us know if you still have any concern. Thanks.
-Pleaase kindly accept the answer if you feel helpful to support the community, thanks a lot.