This is due to an encoding issue with your CSV. You should download the exported WooCommerce products CSV and directly edit it via Excel. Using Google Sheets causes the encoding to be in ASCII and is not understandable by our software. You should also be able to open the incorrectly encoded file in Excel and save as CSV to fix the issue. We are familiar with the encoding errors as we work with several clients that had similar issues. Feel free to contact our support for us to further assist you.