Send me your logfiles via Settings > Create Support Email. I can then take a look at what happened.
Generally: Never forget to make regular backups. Cloud Sync is not a replacement for backups.
You could try to restore everything with these steps:
1) Turn off cloud sync on all devices
2) Delete Stage Traxx 3 from iCloud in iOS/macOS Settings > iCloud > Manag Storage > Stage Traxx 3
3) Restore a time machine backup of the folder ~/Library/Containers/Stage Traxx 3
After that create a new full backup in Stage Traxx before doing anything else.