When deleting customer stations, if that customer station is being used in other features of the system, such as Flat Rate tables or Operating Schedules, the system won't let you delete it. The system should display an error message on the top right corner of the screen, as shown in the screenshot below.
A quick solution is to rename the customer station inserting [IN] - short for Inactive - in front of the customer station's name, as shown on the screenshot below for station #00381.