If you have the "Made with Itsalive" watermark even after deleting your bot (or the itsalive Facebook app) from your Facebook page, it is because we cannot communicate with your Facebook page anymore and update the persistent menu of your chatbot.
If you want to delete your chatbot you need to follow these steps:
Make sure your Bot is connected to your Facebook page (link it back if you have already deleted it)
Then go to your itsalive account in the "Link My bot" tab and click the "Unlink" button.
Once your bot isn't connected anymore it will be switched OFF automatically. Then, you can delete your bot or the itsalive Facebook app but you will lose all your data.