silent attrition
Silent attrition is a situation in which a customer stops patronizing a business without any explanation.
According to Andrea J. Ayers, president of customer management at Convergys:
Silent attrition varies by industry, but in general, companies are losing about 12% of their customers this way, with the defectors poisoning the well among potential new customers. Silent attrition, particularly in this economy, can spell the difference between a company's success and its failure.