Guide to Churn Prediction : Part 1 -- Gather & Clean

It's a telecommunications company that provides home phone and internet services to residents in the USA. The company noticed that their customers have been churning for a while. And this has impacted their customer base and business revenue, hence they need a plan to retain their customers. What do they mean by Customer Churn or Churned Customers? People who stopped using their home phone and internet services are known as churned customers.