You are able to mark customers you are not currently servicing as inactive.
To learn how to mark Customers as inactive, click here.
To generate a report to show your Inactive customers, click Reports in the left menu.
In the Other Reports section, click Inactive Customers.
Select the Date Range you would like to be on the report.
The report lists your inactive customers with the date they became inactive and the reason. 
Use the Export dropdown to download an Excel or CSV file, or Download / Print to download a PDF or print it. 