To uninstall the app, please go to Admin ⇒ Apps => Product Labels Pro.
In case you forget to Restore all content from the theme, you can delete the code by editing the theme.
Go to file: layout/theme.liquid
Find the code {% include 'bss-product-labels-configs' %} and remove it.
Also, remove:
templates/search.bss.product.labels.liquid
snippets/bss-product-labels-configs.liquid
assets/bss_product_labels.js.liquid
Then, Delete the app.
Please don't hesitate to contact us via email sales@bsscommerce.com if you need any further support.
We are more than happy to support you.