Actually, the issue you have reported has been raised due to the incompatibility of WPML with WP Travel cart page as cart page and checkout page provided by WP Travel plugin cannot be translated using WPML. As for now, using WPML you can translate the site in multiple languages but the cart page and checkout page cannot be translated.
Also, we will discuss about this issue and may work on this issue in the future.
We have invested a lot of resources building the site around WP Travel and have counted on it working witg WOML, since it is featured on your website saying that WP Travel is fully compatible with WPML.
We have already built out the site and translated the majority of the content. We are expecting users of different languages to make purchases through our site. It is unacceptable if they spend time shopping and adding items to cart only to be unable to pay at checkout.
We need a solution to allow users on other languages to be able to make payments. Please let us know what we can do to make that work.