If you receive errors regarding the products when trying to import reviews, please make sure that the product identification values included in your file are correct.
Only one of the 2 values either product_handle or product_id is required to successfully import the reviews.
You also want to make sure that your products are correctly synced (please check this article for detailed instructions on product synchronization).
The product handle is the last part of the product URL. For example, for www.yourshop.com/products/red-widget, the product handle is red-widget.
To find the WooCommerce product ID of a product:
• Go to your WooCommcerce admin, Products tab
• Hover over any product to see the product ID (e.g. ID: 122)