Help with OLD Woocommerce problem

Got a site that was built 10+ years ago and running a very old version of WooCommerce. We're having issues with the "Add To Cart" not actually adding products to the cart. Just need someone to take a look and resolve this issue. We are NOT looking to update WooCommerce etc at this stage as we are planning a full rebuild in a few months, but just need this functionality repaired temporarily.

Please ONLY bid if you have experience with older versions of WooCommerce and can understand the customisations made via functions.php and custom WooCommerce templates.