Customer Attrition (n): Customer attrition, also known as customer churn, customer turnover, or customer defection, is a business term used to describe loss of clients or customers. -- Wikipedia
Once a customer has left is there anything you can do to win them back? The answer may be yes and it may be no, but the more interesting question is why did they leave in the first place?
If knowing is half the battle, in this case, it’s three-quarters. Each time a customer votes with their dollar, they are sending you a message and giving you an opportunity—often to learn more than you could if they were still among your devoted following. Being able to take advantage of the opportunity requires that you have a process in place that allows you to move into action quickly and ask the questions that garner you the most valuable information.