How are you checking in cpanel? Through the one click / softaculous installer or through the file manager or phpmyadmin? Any of those will tell you if WP is installed or not.... If you see WP files installed, but the site isn't loading up, an automated upgrade or something might have broke a plugin causing site not to load.
If you still have wp related files, turn off plugins (rename plugins folder) reinstall wp core files directly through ftp, file manager or ssh. Login and reactivate plugins one by one.
If there's no files anywhere, you'll need to restore from a backup or ask host for help in restoring