Hi,
The cart table in the checkout has been made responsive already in HikaShop 2.3.5. So it should display correctly on mobile phones. If that's not the case, it means that either you or our Joomla template has made a customization of the "cart" file of the "checkout" view via the menu Display>Views of HikaShop with an old version of HikaShop.
Deleting the customization in order to use the default view of HikaShop 2.4.0 will make it responsive (display well on mobile phones) but I would recommend to first talk with the person who made the customization either on your end or with your Joomla template provider to check if that's ok.
For the cart page of the user control panel, we didn't work on that yet. It's still on our todo list. If you want to do it, it's possible but it will require custom CSS code to be added to your website using the @media CSS query:
www.hikashop.com/support/support/documen...ize-the-display.html
line25.com/tutorials/create-a-responsive...n-with-media-queries