Fix conflict between wordpress plugins without deactivating them.

I need to use the "Advanced Classifieds and Directory Pro" plugin to build Classifieds on my website. It must be integrated with Woocommerce so the advertisers can buy their own Classifieds plans. This is done using another (paid) plugin called "ACADP - WooCommerce Plans". I have bought, installed and configured all the plugins according to the developer's instructions. The problem is: when I activate and integrate the ACADP, the "add to cart" button on the product page disapears. I have checked the single product PHP file, and even reinstalled the whole Woocommerce, but the thing won't work. The whole website is slow, I know... we will be working on making it faster latter, but first we need to fix this.