Hello, @Duowatt,
Which plugin you have used for that WooCommerce payment? Could you please share the name of the plugin and URL and also please share the screenshot of the issue and I need your site WP Admin Login details in the private content area of this topic as below listed format, so that I will check it for you and help you out if possible.
WP Admin URL:
WP Admin Username:
WP Admin Password:
Note: I need the debugging on your site as well, which includes deactivating all the third-party plugins and on-site Customization as well, so please take the complete backup of your site and share the permission OR clone your site and share that with me.
Regards 8Themes Team.