Logs files is in the root for you site folder logs/

Regarding the recurring problem: I think you may have restored data where the uninstallation process had already started but was not completed. As a result, there might be a few records in the cron database related to the uninstallation process, and when you restored the backup, they ran again.

You might want to try restoring only the Messenger tables manually instead of restoring the entire backup.