This module is to show HikaShop content such as category/product listings in a module instead of in the component area. Other than giving you additional options such as carousel and else, it uses the same views - hence, override features. So, you should follow the usual procedures to create overrides of existing layouts, or new ones to apply to modules.
Also the module doesn't seem to show the product description anymore or the read more link
You might have altered main and/or default configuration options, or chosen a different layout option for the module in question. It's impossible to say more without seeing the site and/or a screenshot of the module configuration.
Needless to say that it's also impossible to say more if you have modified the mod_hikashop files, indeed. First, remove such "customisation" and see if that improves things. Quite frankly, there isn't much good reason I can think of for messing with those files...