According to the studies, if your product has more than 10% bad reviews (one or two star) you'll lose over than 30% of your prospective customers. A ratio of over 35% bad reviews will effectively kill the selling of your product (over 95% loss).
On the other hand over 50% of the disgruntled clients will edit or delete their negative reviews if your customer support team will communicate in a timely manner (first 24 hours), while the risk of losing prospects will be at least 60% lower.