1. Uninstall Syncio via the app
Access your Syncio app and click on the My Account link in the top navigational bar.
Click on the Uninstall App button and follow the instructions.
2. Revoke API access keys related to Syncio
You will then need to delete any API keys that Syncio was using.
In your WooCommerce store admin navigate to:
WooCommerce / Settings / Advanced / REST API
From there search up any Syncio API key and click on revoke to delete it.