Tell customers it will be easy to do business with your firm. When they have an issue come up after the sale, your goal is to resolve it five minutes (you pick the goal or time period). Make it easy for your customers to complain and reach you and make it easy for them to get resolution to their product problem. As an example, promise customers that 99% of complaints can be solved in five minutes or less. If that does not work, choose a goal and state it clearly for your customers to establish yourself as a reputable firm to do business with.