Obviously, any business wants to avoid that and in today’s world, that can be even harder with the ease, amount, and avenues for communication between customers. There are site like Yelp and others, dedicated to collecting feedback and sharing it with the masses.
So here is what you do: load up those mouths with your story. Give people an experience with your product that you would be proud to have them retell. Inject your own story into their experience, what are the values, what are you solving, how is being your patron helping the world. It is all about giving them a reason to feel good about being your customer and providing the matching positive experience as they purchase your product.
If you can turn even just one customer into an ambassador for you, they have the potential to be far more effective than any ad campaign could hope to be.
The idea is to promote yourself by having others promote you.