Focus on delivering a good product. If the product is a failure, try to accept and work on it rather than hiding your failure. This will help for a long run. There is zero chances of getting 100% good reviews, thus keep all the reviews (positive and negative) as such rather than deleting it (online sales). This creates a trust to the customers. Only if the review is vulgar or any use of profanity then delete those reviews. Understand customer's point and try to overcome his burden. Don't pile him with the companies policies when it's not even needed.