As a retailer myself, I always reference the golden rules of business.

1. The customer is always right
2. If the customer is wrong, refer to rule #1

but there is a little known, unwritten third rule. . .

3. The customer is never right if they are not your customer

that being said, a retailer must acknowledge that there are those in the world that will never be satisfied with the quality of your goods or services, and therefore should never be your customer.

I look forward to one-day doing business with you.