This will be done in three steps. First you must delete all products in iZettle and then remove all UUIDs linking a product in WooCommerce to products in iZettle. The final step is to synchronize all products from WooCommerce to iZettle.
Delete all iZettle products
Login into your iZettle account a go to Products .
Check to top left checkbox to select all products. Then click Delete/Remove button.
In your WooCommerce go to iWooCommerce->iZettle. Enable debug mode.
Click on Products tab. Then click on Clear products mapping.
This will remove the link to between WooCommerce products and iZettle products.