Hello Anastasia,
1. We believe the checkout page is now functioning correctly. The issue was caused by a conflict with the Advanced Layout settings located under Theme Options > WooCommerce (Shop) > Cart/Checkout Page > Advanced Layout: https://prnt.sc/mUZbQfvymY6T.
2. To modify the text, please edit your header using Elementor, then select the cart element and update the text as needed: https://prnt.sc/Mekw4Bwgrg9b.
3. Could you please provide the product URL?
Thank you.
Best regards,
8Theme Team