In the last month the expired miles (the last day of March, June, September, December). There are not enough staff members. Make the service slow and dissatisfied customers.
During the mileage expiration. (The last day of March, June, September, December) are not enough staff members. The service delays and create frustration for customers as well.
During the months that miles expire. (the last day of March, June, September to December) is not sufficient to staff members. The service delay and offensive to the customer very much.