I have been in contact with 'Casual games Support' and received several emails suggesting i uninstall Xbox and Sudoku, shut down, wait, restart etc. No joy. Another suggestion was to find Local State and Temp state files, Zip the files and forward them via reply, if the files are too large use OneDrive.
I don't use OneDrive, preferring to store my stuff on my other machine and don't trust Privacy statements and policies.
The zipped files were huge, one was over 600Mb, I explained this and received another mail asking to go back to step one. All in a strange iteration of English which sometimes made it difficult to read.
The strange thing is uninstalling still leaves your setup and stats files on your computer, not their server. Huge data files taking up large spaces on hard bought disc's
I replied that i was fed up being messed about and i would uninstall and not play again,
Until there is news that the problem has been sorted.