HomeRoots Dropshipping Lister

When you add a product to your cart to checkout, it says, Out of Stock and the item is removed from the cart. Nobody can check out using this app. We installed it on 2 websites and neither one works. We have sent 3 messages now a week ago, and no response at all! If people can't checkout, it's all useless and I paid for the full subscription for both sites!